Groundwater quality in the approximately 1,500 square-mile Mojave (MOJO) study unit was investigated from February to April 2008, as part of the Priority Basin Project of the Groundwater Ambient Monitoring and Assessment (GAMA) Program. The GAMA Priority Basin Project was developed in response to the Groundwater Quality Monitoring Act of 2001 and is being conducted by the U.S. Geological Survey (USGS) in cooperation with the California State Water Resources Control Board (SWRCB). MOJO was the 23rd of 37 study units to be sampled as part of the GAMA Priority Basin Project.
The MOJO study was designed to provide a spatially unbiased assessment of the quality of untreated ground water used for public water supplies within MOJO, and to facilitate statistically consistent comparisons of groundwater quality throughout California. Samples were collected from 59 wells in San Bernardino and Los Angeles Counties. Fifty-two of the wells were selected using a spatially distributed, randomized grid-based method to provide statistical representation of the study area (grid wells), and seven were selected to aid in evaluation of specific water-quality issues (understanding wells).
The groundwater samples were analyzed for a large number of organic constituents [volatile organic compounds (VOCs), pesticides and pesticide degradates, and pharmaceutical compounds], constituents of special interest (perchlorate and N-nitrosodimethylamine [NDMA]) naturally occurring inorganic constituents (nutrients, dissolved organic carbon [DOC], major and minor ions, silica, total dissolved solids [TDS], and trace elements), and radioactive constituents (gross alpha and gross beta radioactivity, radium isotopes, and radon-222). Naturally occurring isotopes (stable isotopes of hydrogen, oxygen, and carbon, stable isotopes of nitrogen and oxygen in nitrate, and activities of tritium and carbon-14), and dissolved noble gases also were measured to help identify the sources and ages of the sampled ground water. In total, over 230 constituents and water-quality indicators (field parameters) were investigated.
Three types of quality-control samples (blanks, replicates, and matrix spikes) each were collected at approximately 5–8 percent of the wells, and the results for these samples were used to evaluate the quality of the data for the groundwater samples. Field blanks rarely contained detectable concentrations of any constituent, suggesting that contamination was not a significant source of bias in the data for the groundwater samples. Differences between replicate samples generally were within acceptable ranges, indicating acceptable analytical reproducibility. Matrix spike recoveries were within acceptable ranges for most compounds.
This study did not attempt to evaluate the quality of water delivered to consumers; after withdrawal from the ground, untreated groundwater typically is treated, disinfected, or blended with other waters to maintain water quality. Regulatory thresholds apply to water that is served to the consumer, not to untreated ground water. However, to provide some context for the results, concentrations of constituents measured in the untreated ground water were compared with regulatory and non-regulatory health-based thresholds established by the U.S. Environmental Protection Agency (USEPA) and California Department of Public Health (CDPH) and thresholds established for aesthetic and technical concerns by CDPH. Comparisons between data collected for this study and thresholds for drinking-water are for illustrative purposes only, and are not indicative of compliance or non-compliance with those thresholds.
Most constituents that were detected in groundwater samples in the 59 wells in MOJO were found at concentrations below drinking-water thresholds. In MOJO’s 52 grid wells, volatile organic compounds (VOCs) were detected in 40 percent of the wells, and pesticides and pesticide degradates were detected in 23 percent of the grid wells. Results for health-based thresholds in MOJO grid wells showed that all of the detections of organic compounds in samples from MOJO grid wells were below health-based thresholds, with the exception of a single detection of NDMA above the California Department of Public Health notification level (NL-CA).
Trace elements and radioactive constituents were sampled for at 19 MOJO grid wells and most detections were below health-based thresholds. Exceptions include: six detections of arsenic above the USEPA maximum contaminant level (MCL-US), two detections of boron and one detection of vanadium above the NL-CA, one detection each of molybdenum and strontium that were above the USEPA lifetime health advisory level (HAL-US), and one detection of fluoride just above the MCL-CA of 2 µg/L. Most detections of radioactive constituents in the MOJO grid wells were below health-based thresholds, with the exception of one detection of gross alpha radioactivity (72-hour count and 30-day count) above the MCL-CA, and 17 grid wells (of 19 sampled) that had activities of radon-222 above the proposed MCL-US of 300 pCi/L, but all were below the proposed alternative MCL-US of 4,000 pCi/L.
All of the samples collected from the 19 MOJO grid wells for trace elements, and most of the samples for major ions and total dissolved solids (TDS), had measured concentrations below the non-enforceable thresholds set for aesthetic concerns. Four grid wells had TDS concentrations above the California Department of Public Health secondary maximum contaminant level (SMCL-CA) recommended threshold of 500 mg/L, and three of these wells were also above the SMCL-CA upper threshold of 1,000 mg/L. Four grid wells (of 19 sampled) had sulfate measured at concentrations above the recommended SMCL-CA threshold of 250 mg/L, and one of these detections was also above the upper SMCL-CA threshold of 500 mg/L. One grid well had chloride levels at a concentration above the upper SMCL-CA threshold of 500 mg/L. Eleven grid wells (of 52 sampled) had pH values outside of the SMCL-US range for pH.
","language":"English","publisher":"U.S. Geological Survey","doi":"10.3133/ds440","collaboration":"Prepared in cooperation with the California State Water Resources Control Board; A product of the California Groundwater Ambient Monitoring and Assessment (GAMA) Program","usgsCitation":"Mathany, T., and Belitz, K., 2009, Groundwater quality data in the Mojave study unit, 2008: Results from the California GAMA Program: U.S. Geological Survey Data Series 440, x, 81 p., https://doi.org/10.3133/ds440.","productDescription":"x, 81 p.","temporalStart":"2008-02-01","temporalEnd":"2008-04-30","costCenters":[{"id":154,"text":"California Water Science Center","active":true,"usgs":true}],"links":[{"id":118585,"rank":0,"type":{"id":24,"text":"Thumbnail"},"url":"https://pubs.usgs.gov/thumbnails/ds_440.jpg"},{"id":13086,"rank":100,"type":{"id":11,"text":"Document"},"url":"https://pubs.usgs.gov/ds/440/","text":"Index page","linkFileType":{"id":5,"text":"html"}},{"id":360778,"rank":3,"type":{"id":11,"text":"Document"},"url":"https://pubs.usgs.gov/ds/440/pdf/ds440.pdf","text":"Report","size":"12.3 MB","linkFileType":{"id":1,"text":"pdf"}}],"country":"United States","state":"California","otherGeospatial":"Mojave study unit","geographicExtents":"{\n \"type\": \"FeatureCollection\",\n \"features\": [\n {\n \"type\": \"Feature\",\n \"properties\": {},\n \"geometry\": {\n \"type\": \"Polygon\",\n \"coordinates\": [\n [\n [\n -117.7333,\n 34.2833\n ],\n [\n -116.35,\n 34.2833\n ],\n [\n -116.35,\n 35.0708\n ],\n [\n -117.7333,\n 35.0708\n ],\n [\n -117.7333,\n 34.2833\n ]\n ]\n ]\n }\n }\n ]\n}","noUsgsAuthors":false,"publicationStatus":"PW","scienceBaseUri":"4f4e4a95e4b07f02db659f54","contributors":{"authors":[{"text":"Mathany, Timothy M. 0000-0002-4747-5113","orcid":"https://orcid.org/0000-0002-4747-5113","contributorId":99949,"corporation":false,"usgs":true,"family":"Mathany","given":"Timothy M.","affiliations":[],"preferred":false,"id":303577,"contributorType":{"id":1,"text":"Authors"},"rank":1},{"text":"Belitz, Kenneth 0000-0003-4481-2345 kbelitz@usgs.gov","orcid":"https://orcid.org/0000-0003-4481-2345","contributorId":442,"corporation":false,"usgs":true,"family":"Belitz","given":"Kenneth","email":"kbelitz@usgs.gov","affiliations":[{"id":27111,"text":"National Water Quality Program","active":true,"usgs":true},{"id":466,"text":"New England Water Science Center","active":true,"usgs":true},{"id":451,"text":"National Water Quality Assessment Program","active":true,"usgs":true},{"id":376,"text":"Massachusetts Water Science Center","active":true,"usgs":true},{"id":503,"text":"Office of Water Quality","active":true,"usgs":true}],"preferred":true,"id":303576,"contributorType":{"id":1,"text":"Authors"},"rank":2}]}} ,{"id":97895,"text":"ofr20091182 - 2009 - Mercury, methylmercury, and other constituents in sediment and water from seasonal and permanent wetlands in the Cache Creek settling basin and Yolo Bypass, Yolo County, California, 2005-06","interactions":[],"lastModifiedDate":"2019-08-15T12:35:13","indexId":"ofr20091182","displayToPublicDate":"2009-10-03T00:00:00","publicationYear":"2009","noYear":false,"publicationType":{"id":18,"text":"Report"},"publicationSubtype":{"id":5,"text":"USGS Numbered Series"},"seriesTitle":{"id":330,"text":"Open-File Report","code":"OFR","onlineIssn":"2331-1258","printIssn":"0196-1497","active":true,"publicationSubtype":{"id":5}},"seriesNumber":"2009-1182","title":"Mercury, methylmercury, and other constituents in sediment and water from seasonal and permanent wetlands in the Cache Creek settling basin and Yolo Bypass, Yolo County, California, 2005-06","docAbstract":"This report presents surface water and surface (top 0-2 cm) sediment geochemical data collected during 2005-2006, as part of a larger study of mercury (Hg) dynamics in seasonal and permanently flooded wetland habitats within the lower Sacramento River basin, Yolo County, California. The study was conducted in two phases. Phase I represented reconnaissance sampling and included three locations within the Cache Creek drainage basin; two within the Cache Creek Nature Preserve (CCNP) and one in the Cache Creek Settling Basin (CCSB) within the creek's main channel near the southeast outlet to the Yolo Bypass. Two additional downstream sites within the Yolo Bypass Wildlife Area (YBWA) were also sampled during Phase I, including one permanently flooded wetland and one seasonally flooded wetland, which had began being flooded only 1–2 days before Phase I sampling.
Results from Phase I include: (a) a negative correlation between total mercury (THg) and the percentage of methylmercury (MeHg) in unfiltered surface water; (b) a positive correlation between sediment THg concentration and sediment organic content; (c) surface water and sediment THg concentrations were highest at the CCSB site; (d) sediment inorganic reactive mercury (Hg(II)R) concentration was positively related to sediment oxidation-reduction potential and negatively related to sediment acid volatile sulfur (AVS) concentration; (e) sediment Hg(II)R concentrations were highest at the two YBWA sites; (f) unfiltered surface water MeHg concentration was highest at the seasonal wetland YBWA site, and sediment MeHg was highest at the permanently flooded YBWA site; (g) a 1,000-fold increase in sediment pore water sulfate concentration was observed in the downstream transect from the CCNP to the YBWA; (h) low sediment pore water sulfide concentrations (<1 µmol/L) across all sites; and (i) iron (Fe) speciation data suggest a higher potential for microbial Fe(III)-reduction in the YBWA compared to the CCSB.
Phase II sampling did not include the original three Cache Creek sites, but instead focused on the original two sites within the YBWA and a similarly paired set of seasonally and permanently flooded wetland sites within the CCSB. Sediment sampling at the YBWA and CCSB occurred approximately 28 days and 52 days, respectively, after the initial flooding of the respective seasonal wetlands, and again towards the end of the seasonal flooding period (end of May 2006). Results from Phase II sampling include: (a) sediment MeHg concentration and the percentage of THg as MeHg (%MeHg) in unfiltered surface waters were generally higher in the YBWA compared to the CCSB; (b) suspended sediment concentration (SCC) in surface water was positively correlated with both THg and MeHg in unfiltered water across all sites, although the relationship between SCC and MeHg differed for the two regions, suggesting local MeHg sources; (c) MeHg concentration in unfiltered surface water was positively correlated to sediment MeHg concentrations across all sites, supporting the suggestion of unique local (sediment) sources of MeHg to the water column; (d) THg concentration in filtered water was positively correlated with both total Fe and dissolved organic carbon (DOC), offering additional support for the role of these constituents in the partitioning of THg between particulate and dissolved phases; (e) flooding of the YBWA seasonal wetland resulted in a rapid and significant (5-fold) rise in sediment MeHg concentration within 3–4 weeks following inundation; and (f) temporal changes in sediment S and Fe speciation suggest that rates of both microbial sulfate reduction and Fe(III)-reduction were significantly higher at YBWA, compared to CCSB, during the period between flooding and drying.
The geochemical data presented in this report indicate that (a) strong spatial and temporal differences in Hg speciation and transformations can occur within the range of wetland habitats found in the lower Sacramento River basin; (b) flooding of seasonal wetlands can be accompanied by a rapid increase in benthic MeHg production and the release of previously formed MeHg (generated during or since the previous flooding season) to the overlying water column; (c) S and Fe chemistry, and associated microbial reduction pathways, play an important role in mediating the speciation and transformation of Hg in these wetland habitats; (d) hydroperiod is a primary forcing function in mediating MeHg production among various wetland types; and (e) MeHg production appears to be more active in the YBWA compared to the CCSB.
","language":"English","publisher":"U.S. Geological Survey","publisherLocation":"Reston, VA","doi":"10.3133/ofr20091182","collaboration":"Prepared in cooperation with the Sacramento Regional County Sanitation District, the Sacramento River Watershed Program, and the United States Environmental Protection Agency","usgsCitation":"Marvin-DiPasquale, M., Alpers, C.N., and Fleck, J., 2009, Mercury, methylmercury, and other constituents in sediment and water from seasonal and permanent wetlands in the Cache Creek settling basin and Yolo Bypass, Yolo County, California, 2005-06: U.S. Geological Survey Open-File Report 2009-1182, xi, 69 p., https://doi.org/10.3133/ofr20091182.","productDescription":"xi, 69 p.","onlineOnly":"Y","temporalStart":"2005-01-01","temporalEnd":"2006-12-31","costCenters":[{"id":154,"text":"California Water Science Center","active":true,"usgs":true},{"id":434,"text":"National Research Program","active":false,"usgs":true},{"id":589,"text":"Toxic Substances Hydrology Program","active":true,"usgs":true}],"links":[{"id":118532,"rank":0,"type":{"id":24,"text":"Thumbnail"},"url":"https://pubs.usgs.gov/thumbnails/ofr_2009_1182.jpg"},{"id":352998,"rank":3,"type":{"id":11,"text":"Document"},"url":"https://pubs.usgs.gov/of/2009/1182/of2009-1182.pdf"},{"id":13069,"rank":100,"type":{"id":15,"text":"Index Page"},"url":"https://pubs.usgs.gov/of/2009/1182/","linkFileType":{"id":5,"text":"html"}}],"country":"United States","state":"California","county":"Yolo County","otherGeospatial":"Cache Creek settling basin, Yolo Bypass","geographicExtents":"{ \"type\": \"FeatureCollection\", \"features\": [ { \"type\": \"Feature\", \"properties\": {}, \"geometry\": { \"type\": \"Polygon\", \"coordinates\": [ [ [ -121.96666666666667,38.46666666666667 ], [ -121.96666666666667,38.75 ], [ -121.5,38.75 ], [ -121.5,38.46666666666667 ], [ -121.96666666666667,38.46666666666667 ] ] ] } } ] }","noUsgsAuthors":false,"publicationStatus":"PW","scienceBaseUri":"4f4e4a4ae4b07f02db624dcb","contributors":{"authors":[{"text":"Marvin-DiPasquale, Mark 0000-0002-8186-9167 mmarvin@usgs.gov","orcid":"https://orcid.org/0000-0002-8186-9167","contributorId":149175,"corporation":false,"usgs":true,"family":"Marvin-DiPasquale","given":"Mark","email":"mmarvin@usgs.gov","affiliations":[{"id":438,"text":"National Research Program - Western Branch","active":true,"usgs":true}],"preferred":true,"id":303517,"contributorType":{"id":1,"text":"Authors"},"rank":1},{"text":"Alpers, Charles N. 0000-0001-6945-7365 cnalpers@usgs.gov","orcid":"https://orcid.org/0000-0001-6945-7365","contributorId":411,"corporation":false,"usgs":true,"family":"Alpers","given":"Charles","email":"cnalpers@usgs.gov","middleInitial":"N.","affiliations":[{"id":154,"text":"California Water Science Center","active":true,"usgs":true}],"preferred":true,"id":303515,"contributorType":{"id":1,"text":"Authors"},"rank":2},{"text":"Fleck, Jacob A. 0000-0002-3217-3972 jafleck@usgs.gov","orcid":"https://orcid.org/0000-0002-3217-3972","contributorId":1498,"corporation":false,"usgs":true,"family":"Fleck","given":"Jacob A.","email":"jafleck@usgs.gov","affiliations":[{"id":154,"text":"California Water Science Center","active":true,"usgs":true}],"preferred":false,"id":303516,"contributorType":{"id":1,"text":"Authors"},"rank":3}]}} ,{"id":97887,"text":"ofr20091141 - 2009 - Selected Natural Attenuation Monitoring Data, Operable Unit 1, Naval Undersea Warfare Center, Division Keyport, Washington, 2007 and 2008","interactions":[],"lastModifiedDate":"2012-03-08T17:16:25","indexId":"ofr20091141","displayToPublicDate":"2009-10-01T00:00:00","publicationYear":"2009","noYear":false,"publicationType":{"id":18,"text":"Report"},"publicationSubtype":{"id":5,"text":"USGS Numbered Series"},"seriesTitle":{"id":330,"text":"Open-File Report","code":"OFR","onlineIssn":"2331-1258","printIssn":"0196-1497","active":true,"publicationSubtype":{"id":5}},"seriesNumber":"2009-1141","title":"Selected Natural Attenuation Monitoring Data, Operable Unit 1, Naval Undersea Warfare Center, Division Keyport, Washington, 2007 and 2008","docAbstract":"Previous investigations indicate that natural attenuation and biodegradation of chlorinated volatile organic compounds (VOCs) are substantial in groundwater beneath the 9-acre former landfill at Operable Unit 1 (OU 1), Naval Undersea Warfare Center, Division Keyport, Washington. Phytoremediation combined with on-going natural attenuation processes was the preferred remedy selected by the Navy, as specified in the Record of Decision for the site. The Navy planted two hybrid poplar plantations on the landfill in spring 1999 to remove and to control the migration of chlorinated VOCs in shallow groundwater. The U.S. Geological Survey (USGS) has continued to monitor groundwater geochemistry to ensure that conditions remain favorable for contaminant biodegradation as specified in the Record of Decision. In this report are groundwater geochemical and selected VOC data collected at OU 1 by the USGS during June 18-21, 2007, and June 16-18, 2008, in support of long-term monitoring for natural attenuation.\r\n\r\nFor 2007 and 2008, strongly reducing conditions (sulfate reduction and methanogenesis) most favorable for reductive dechlorination of VOCs were inferred for 9 of 16 upper-aquifer wells and piezometers in the northern and southern phytoremediation plantations. Predominant redox conditions in groundwater from the intermediate aquifer just downgradient from the landfill remained mildly reducing and somewhat favorable for reductive dechlorination of VOCs. Dissolved hydrogen (H2) concentrations measured in the upper aquifer during 2007 and 2008 generally have been lower than H2 concentrations measured before 2002. However, widespread and relatively high methane and sulfide concentrations indicate that the lower H2 concentrations measured do not support a trend from strongly to mildly reducing redox conditions because no widespread changes in groundwater redox conditions were identified that should result in less favorable conditions for the reductive dechlorination of the chlorinated VOCs.\r\n\r\nFor the upper aquifer beneath the northern phytoremediation plantation, chlorinated VOC concentrations in 2007 and 2008 at most piezometers were similar to or slightly less than chlorinated VOC concentrations measured in previous years. The only chlorinated VOC positively detected at piezometers P1-1 and P1-5 was cis-1,2-dichloroethene (cis-DCE); most chlorinated VOC concentrations at piezometer P1-3 were at the lowest levels since monitoring began in 1999. Most VOC concentrations at piezometer P1-4 were similar to VOC concentrations measured in previous years except that vinyl chloride (VC) concentrations inexplicably increased from 280 micrograms per liter (ug/L) in June 2007 to 750 ug/L in June 2008. In 2008, measurement of the sum of concentrations of ethane and ethene, reductive dechlorination byproducts, was at the highest level at most northern plantation wells and piezometers, which is evidence of reductive dechlorination of chlorinated VOCs.\r\n\r\nFor the upper aquifer beneath the southern phytoremediation plantation, chlorinated VOC concentrations in 2007 and 2008 at the piezometers were most often extremely high and they continued to vary considerable over space and between years. At piezometer P1-6, the total chlorinated VOC concentration increased from 380 ug/L in 2007 to more than 20,000 ug/L in 2008. At piezometer P1-7 in 2008, the concentrations of trichloroethene, cis-DCE, and VC were the highest to date, but total chlorinated VOC concentrations at piezometers P1-8, P1-9, and P1-10 in 2008 were relatively low compared to historical levels. The magnitude and persistence of chlorinated VOC concentrations indicate that non-aqueous phase liquid chloroethenes likely are beneath the southern plantation, and the temporal variability in concentrations likely is a result of variations in precipitation and groundwater levels interacting with the non-aqueous phase liquid. The reductive dechlorination byproducts ethane and ethene were detected at ","language":"ENGLISH","publisher":"U.S. Geological Survey","doi":"10.3133/ofr20091141","collaboration":"Prepared in cooperation with Department of the Navy, Naval Facilities Engineering Command, Northwest","usgsCitation":"Dinicola, R., and Huffman, R., 2009, Selected Natural Attenuation Monitoring Data, Operable Unit 1, Naval Undersea Warfare Center, Division Keyport, Washington, 2007 and 2008: U.S. Geological Survey Open-File Report 2009-1141, iv, 43 p., https://doi.org/10.3133/ofr20091141.","productDescription":"iv, 43 p.","temporalStart":"2007-06-18","temporalEnd":"2008-06-18","costCenters":[{"id":622,"text":"Washington Water Science Center","active":true,"usgs":true}],"links":[{"id":118512,"rank":0,"type":{"id":24,"text":"Thumbnail"},"url":"https://pubs.usgs.gov/thumbnails/ofr_2009_1141.jpg"},{"id":13062,"rank":100,"type":{"id":15,"text":"Index Page"},"url":"https://pubs.usgs.gov/of/2009/1141/","linkFileType":{"id":5,"text":"html"}}],"geographicExtents":"{ \"type\": \"FeatureCollection\", \"features\": [ { \"type\": \"Feature\", \"properties\": {}, \"geometry\": { \"type\": \"Polygon\", \"coordinates\": [ [ [ -122.63388888888889,47.683611111111105 ], [ -122.63388888888889,47.70111111111111 ], [ -122.60083333333333,47.70111111111111 ], [ -122.60083333333333,47.683611111111105 ], [ -122.63388888888889,47.683611111111105 ] ] ] } } ] }","noUsgsAuthors":false,"publicationStatus":"PW","scienceBaseUri":"4f4e4a09e4b07f02db5fa7d6","contributors":{"authors":[{"text":"Dinicola, R.S.","contributorId":64290,"corporation":false,"usgs":true,"family":"Dinicola","given":"R.S.","email":"","affiliations":[],"preferred":false,"id":303489,"contributorType":{"id":1,"text":"Authors"},"rank":1},{"text":"Huffman, R.L.","contributorId":44956,"corporation":false,"usgs":true,"family":"Huffman","given":"R.L.","email":"","affiliations":[],"preferred":false,"id":303488,"contributorType":{"id":1,"text":"Authors"},"rank":2}]}} ,{"id":70003854,"text":"70003854 - 2009 - Magma evolution and ascent at the craters of the moon and neighboring volcanic fields, southern Idaho, USA: Implications for the evolution of polygenetic and monogenetic volcanic fields","interactions":[],"lastModifiedDate":"2021-03-05T18:13:52.41254","indexId":"70003854","displayToPublicDate":"2009-09-30T00:00:00","publicationYear":"2009","noYear":false,"publicationType":{"id":2,"text":"Article"},"publicationSubtype":{"id":10,"text":"Journal Article"},"seriesTitle":{"id":2420,"text":"Journal of Petrology","active":true,"publicationSubtype":{"id":10}},"title":"Magma evolution and ascent at the craters of the moon and neighboring volcanic fields, southern Idaho, USA: Implications for the evolution of polygenetic and monogenetic volcanic fields","docAbstract":"The evolution of polygenetic and monogenetic volcanic fields must reflect differences in magma processing during ascent. To assess their evolution we use thermobarometry and geochemistry to evaluate ascent paths for neighboring, nearly coeval volcanic fields in the Snake River Plain, in south-central Idaho, derived from (1) dominantly Holocene polygenetic evolved lavas from the Craters of the Moon lava field (COME) and (2) Quaternary non-evolved, olivine tholeiites (NEOT) from nearby monogenetic volcanic fields. These data show that NEOT have high magmatic temperatures (1205 + or - 27 degrees C) and a narrow temperature range (< 25 degrees C) at any given depth; NEOT parent magmas partially crystallize within the middle crust (14-17 km), but with little time for cooling or assimilation. In contrast, COME magmas partially crystallize at similar depths, but at any given depth exhibit lower temperatures (by ~40 degrees C), and wider temperature ranges (>50 degrees C). Prolonged storage of COME magmas allows them to evolve to higher 87Sr/86Sr and SiO2, and lower MgO and 143Nd/144Nd. Most importantly, ascent paths control evolution: NEOT often erupt near the axis of the plain where high-flux (Yellowstone-related), pre-Holocene magmatic activity replaces granitic middle crust with basaltic sills, resulting in a net increase in NEOT magma buoyancy. COME flows erupt off-axis, where felsic crustal lithologies sometimes remain intact, providing a barrier to ascent and a source for crustal contamination. A three-stage ascent process explains the entire range of erupted compositions. Stage 1 (40-20 km): picrites are transported to the middle crust, undergoing partial crystallization of olivine + or - clinopyroxene. COME magmas pass through unarmored conduits and assimilate 1% or less of ancient gabbroic crust having high Sr and 87Sr/86Sr and low SiO2. Stage 2 (20-10 km): magmas are stored within the middle crust, and evolve to moderate MgO (10%). NEOT magmas, reaching 10% MgO, are positively buoyant and migrate through the middle crust. COME magmas remain negatively buoyant and so crystallize further and assimilate middle crust. Stage 3 (15-0 km): final ascent and eruption occurs when volatile contents, increased by differentiation, are sufficient (1-2 wt % H2O) to provide magma buoyancy through the middle (and upper) crust.","language":"English","publisher":"Oxford Journals","doi":"10.1093/petrology/egp045","usgsCitation":"Putirka, K.D., Kuntz, M., Unruh, D., and Vaid, N., 2009, Magma evolution and ascent at the craters of the moon and neighboring volcanic fields, southern Idaho, USA: Implications for the evolution of polygenetic and monogenetic volcanic fields: Journal of Petrology, v. 50, no. 9, p. 1639-1665, https://doi.org/10.1093/petrology/egp045.","productDescription":"27 p.","startPage":"1639","endPage":"1665","costCenters":[{"id":308,"text":"Geology and Environmental Change Science Center","active":false,"usgs":true}],"links":[{"id":476062,"rank":0,"type":{"id":40,"text":"Open Access Publisher Index Page"},"url":"https://doi.org/10.1093/petrology/egp045","text":"Publisher Index Page"},{"id":384097,"type":{"id":24,"text":"Thumbnail"},"url":"https://pubs.usgs.gov/thumbnails/outside_thumb.jpg"}],"country":"United States","state":"Idaho","otherGeospatial":"southern Idaho","geographicExtents":"{\n \"type\": \"FeatureCollection\",\n \"features\": [\n {\n \"type\": \"Feature\",\n \"properties\": {},\n \"geometry\": {\n \"type\": \"Polygon\",\n \"coordinates\": [\n [\n [\n -117.29003906249997,\n 41.902277040963696\n ],\n [\n -111.09374999999999,\n 41.902277040963696\n ],\n [\n -111.09374999999999,\n 45.42929873257375\n ],\n [\n -117.29003906249997,\n 45.42929873257375\n ],\n [\n -117.29003906249997,\n 41.902277040963696\n ]\n ]\n ]\n }\n }\n ]\n}","volume":"50","issue":"9","noUsgsAuthors":false,"publicationDate":"2009-07-13","publicationStatus":"PW","scienceBaseUri":"4f4e4a7fe4b07f02db649213","contributors":{"authors":[{"text":"Putirka, Keith D.","contributorId":89652,"corporation":false,"usgs":true,"family":"Putirka","given":"Keith","email":"","middleInitial":"D.","affiliations":[],"preferred":false,"id":349162,"contributorType":{"id":1,"text":"Authors"},"rank":1},{"text":"Kuntz, Mel A. 0000-0001-8828-5474","orcid":"https://orcid.org/0000-0001-8828-5474","contributorId":6446,"corporation":false,"usgs":true,"family":"Kuntz","given":"Mel A.","affiliations":[],"preferred":false,"id":349160,"contributorType":{"id":1,"text":"Authors"},"rank":2},{"text":"Unruh, Daniel M.","contributorId":96291,"corporation":false,"usgs":true,"family":"Unruh","given":"Daniel M.","affiliations":[],"preferred":false,"id":349163,"contributorType":{"id":1,"text":"Authors"},"rank":3},{"text":"Vaid, Nitin","contributorId":37878,"corporation":false,"usgs":true,"family":"Vaid","given":"Nitin","email":"","affiliations":[],"preferred":false,"id":349161,"contributorType":{"id":1,"text":"Authors"},"rank":4}]}} ,{"id":97856,"text":"ofr20091196 - 2009 - Results of the Analyses for 1,4-Dioxane of Groundwater Samples Collected in the Tucson Airport Remediation Project Area, South-Central Arizona, 2006-2009","interactions":[],"lastModifiedDate":"2012-02-10T00:11:49","indexId":"ofr20091196","displayToPublicDate":"2009-09-29T00:00:00","publicationYear":"2009","noYear":false,"publicationType":{"id":18,"text":"Report"},"publicationSubtype":{"id":5,"text":"USGS Numbered Series"},"seriesTitle":{"id":330,"text":"Open-File Report","code":"OFR","onlineIssn":"2331-1258","printIssn":"0196-1497","active":true,"publicationSubtype":{"id":5}},"seriesNumber":"2009-1196","title":"Results of the Analyses for 1,4-Dioxane of Groundwater Samples Collected in the Tucson Airport Remediation Project Area, South-Central Arizona, 2006-2009","docAbstract":"Extensive groundwater contamination resulting from industrial activities led to the listing of the Tucson International Airport Area (TIAA) as a Superfund Site by the U.S. Environmental Protection Agency (USEPA) in 1983. Early investigations revealed elevated levels of volatile organic compounds (VOCs), including the chlorinated solvents trichloroethylene and perchloroethylene, in wells in the area. Several responsible parties were identified, and cleanup activities were initiated in the late 1980s using technology designed for removal of VOCs. In 2002, the compound 1,4-dioxane was discovered in wells in the TIAA area. Since then, 1,4-dioxane has been detected throughout the TIAA area at levels exceeding the USEPA Drinking Water Health Advisory value of 3 micrograms per liter (ug/L; U.S. Environmental Protection Agency, 2006). Chemical properties of 1,4-dioxane make it relatively unaffected by the treatment technologies employed in the TIAA area. In 2006, the U.S. Geological Survey (USGS) Arizona Water Science Center, in cooperation with the U.S. Air Force Center for Engineering and the Environment, began an investigation into the extent of groundwater contamination by 1,4-dioxane in the area. Five rounds of groundwater sampling in the TIAA area have been completed by the USGS since that time, yielding a total of 210 samples. Results from these analyses indicate less than reportable concentrations of 1,4-dioxane in 30 percent of the samples, with 46 percent of the samples having concentrations at or above the USEPA Drinking Water Health Advisory level.","language":"ENGLISH","publisher":"U.S. Geological Survey","doi":"10.3133/ofr20091196","collaboration":"Prepared in cooperation with the U.S. Air Force Center for Engineering and the Environment-Restoration Program Management Office and the City of Tucson Water Department","usgsCitation":"Tillman, F., 2009, Results of the Analyses for 1,4-Dioxane of Groundwater Samples Collected in the Tucson Airport Remediation Project Area, South-Central Arizona, 2006-2009: U.S. Geological Survey Open-File Report 2009-1196, iv, 14 p., https://doi.org/10.3133/ofr20091196.","productDescription":"iv, 14 p.","onlineOnly":"Y","temporalStart":"2006-01-01","temporalEnd":"2009-12-31","costCenters":[{"id":128,"text":"Arizona Water Science Center","active":true,"usgs":true}],"links":[{"id":125496,"rank":0,"type":{"id":24,"text":"Thumbnail"},"url":"https://pubs.usgs.gov/thumbnails/ofr_2009_1196.jpg"},{"id":13031,"rank":100,"type":{"id":15,"text":"Index Page"},"url":"https://pubs.usgs.gov/of/2009/1196/","linkFileType":{"id":5,"text":"html"}}],"geographicExtents":"{ \"type\": \"FeatureCollection\", \"features\": [ { \"type\": \"Feature\", \"properties\": {}, \"geometry\": { \"type\": \"Polygon\", \"coordinates\": [ [ [ -111.01666666666667,32.083333333333336 ], [ -111.01666666666667,32.18333333333333 ], [ -110.9,32.18333333333333 ], [ -110.9,32.083333333333336 ], [ -111.01666666666667,32.083333333333336 ] ] ] } } ] }","noUsgsAuthors":false,"publicationStatus":"PW","scienceBaseUri":"4f4e4b00e4b07f02db6982bc","contributors":{"authors":[{"text":"Tillman, Fred D. 0000-0002-2922-402X ftillman@usgs.gov","orcid":"https://orcid.org/0000-0002-2922-402X","contributorId":1629,"corporation":false,"usgs":true,"family":"Tillman","given":"Fred D.","email":"ftillman@usgs.gov","affiliations":[{"id":128,"text":"Arizona Water Science Center","active":true,"usgs":true}],"preferred":false,"id":303359,"contributorType":{"id":1,"text":"Authors"},"rank":1}]}} ,{"id":97840,"text":"ds463 - 2009 - Groundwater-quality data in the South Coast Interior Basins study unit, 2008: Results from the California GAMA Program","interactions":[],"lastModifiedDate":"2022-07-19T21:01:03.316013","indexId":"ds463","displayToPublicDate":"2009-09-22T00:00:00","publicationYear":"2009","noYear":false,"publicationType":{"id":18,"text":"Report"},"publicationSubtype":{"id":5,"text":"USGS Numbered Series"},"seriesTitle":{"id":310,"text":"Data Series","code":"DS","onlineIssn":"2327-638X","printIssn":"2327-0271","active":false,"publicationSubtype":{"id":5}},"seriesNumber":"463","title":"Groundwater-quality data in the South Coast Interior Basins study unit, 2008: Results from the California GAMA Program","docAbstract":"Groundwater quality in the approximately 653-square-mile South Coast Interior Basins (SCI) study unit was investigated from August to December 2008, as part of the Priority Basins Project of the Groundwater Ambient Monitoring and Assessment (GAMA) Program. The GAMA Priority Basins Project was developed in response to Legislative mandates (Supplemental Report of the 1999 Budget Act 1999-00 Fiscal Year; and, the Groundwater-Quality Monitoring Act of 2001 [Sections 10780-10782.3 of the California Water Code, Assembly Bill 599]) to assess and monitor the quality of groundwater used as public supply for municipalities in California, and is being conducted by the U.S. Geological Survey (USGS) in cooperation with the California State Water Resources Control Board (SWRCB). SCI was the 27th study unit to be sampled as part of the GAMA Priority Basins Project.
This study was designed to provide a spatially unbiased assessment of the quality of untreated groundwater used for public water supplies within SCI, and to facilitate statistically consistent comparisons of groundwater quality throughout California. Samples were collected from 54 wells within the three study areas [Livermore, Gilroy, and Cuyama] of SCI in Alameda, Santa Clara, San Benito, Santa Barbara, Ventura, and Kern Counties. Thirty-five of the wells were selected using a spatially distributed, randomized grid-based method to provide statistical representation of the study unit (grid wells), and 19 were selected to aid in evaluation of specific water-quality issues (understanding wells).
The groundwater samples were analyzed for organic constituents [volatile organic compounds (VOCs), pesticides and pesticide degradates, polar pesticides and metabolites, and pharmaceutical compounds], constituents of special interest [perchlorate and N-nitrosodimethylamine (NDMA)], naturally occurring inorganic constituents [trace elements, nutrients, major and minor ions, silica, total dissolved solids (TDS), and alkalinity], and radioactive constituents [gross alpha and gross beta radioactivity and radon-222]. Naturally occurring isotopes [stable isotopes of hydrogen, oxygen, and carbon, and activities of tritium and carbon-14] and dissolved noble gases also were measured to help identify the sources and ages of the sampled groundwater. In total, 288 constituents and water-quality indicators (field parameters) were investigated.
Three types of quality-control samples (blanks, replicates, and matrix spikes) each were collected at approximately 4–11 percent of the wells, and the results for these samples were used to evaluate the quality of the data for the groundwater samples. Field blanks rarely contained detectable concentrations of any constituent, suggesting that contamination was not a significant source of bias in the data obtained from the groundwater samples. Differences between replicate samples generally were less than 10 percent relative standard deviation, indicating acceptable analytical reproducibility. Matrix spike recoveries were within the acceptable range (70 to 130 percent) for most compounds.
This study did not attempt to evaluate the quality of water delivered to consumers; after withdrawal from the ground, untreated groundwater typically is treated, disinfected, and/or blended with other waters to maintain water quality. Regulatory thresholds apply to water that is served to the consumer, not to untreated groundwater. However, to provide some context for the results, concentrations of constituents measured in the untreated groundwater were compared with regulatory and nonregulatory health-based thresholds established by the U.S. Environmental Protection Agency (USEPA) and California Department of Public Health (CDPH), and to nonregulatory thresholds established for aesthetic and technical concerns by CDPH. Comparisons between data collected for this study and thresholds for drinking water are for illustrative purposes only, and are not indicative of compliance or noncompliance with those thresholds.
Most inorganic constituents that were detected in groundwater samples from the 35 grid wells in the SCI study unit were found at concentrations below drinking-water thresholds; additionally, all detections of organic constituents in SCI grid well samples were below health-based thresholds.
","language":"English","publisher":"U.S. Geological Survey","doi":"10.3133/ds463","collaboration":"Prepared in cooperation with the California State Water Resources Control Board","usgsCitation":"Mathany, T., Kulongoski, J., Ray, M.C., and Belitz, K., 2009, Groundwater-quality data in the South Coast Interior Basins study unit, 2008: Results from the California GAMA Program: U.S. Geological Survey Data Series 463, xii, 83 p., https://doi.org/10.3133/ds463.","productDescription":"xii, 83 p.","costCenters":[{"id":154,"text":"California Water Science Center","active":true,"usgs":true}],"links":[{"id":118588,"rank":0,"type":{"id":24,"text":"Thumbnail"},"url":"https://pubs.usgs.gov/thumbnails/ds_463.jpg"},{"id":13013,"rank":100,"type":{"id":15,"text":"Index Page"},"url":"https://pubs.usgs.gov/ds/463/","linkFileType":{"id":5,"text":"html"}},{"id":404082,"rank":2,"type":{"id":36,"text":"NGMDB Index Page"},"url":"https://ngmdb.usgs.gov/Prodesc/proddesc_87388.htm","linkFileType":{"id":5,"text":"html"}}],"country":"United States","state":"California","otherGeospatial":"South Coast Interior Basins study unit","geographicExtents":"{\n \"type\": \"FeatureCollection\",\n \"features\": [\n {\n \"type\": \"Feature\",\n \"properties\": {},\n \"geometry\": {\n \"type\": \"Polygon\",\n \"coordinates\": [\n [\n [\n -121.9833,\n 37.5833\n ],\n [\n -121.650,\n 37.5833\n ],\n [\n -121.650,\n 37.7833\n ],\n [\n -121.9833,\n 37.7833\n ],\n [\n -121.9833,\n 37.5833\n ]\n ]\n ]\n }\n }\n ]\n}","noUsgsAuthors":false,"publicationStatus":"PW","scienceBaseUri":"4f4e4a94e4b07f02db658d8f","contributors":{"authors":[{"text":"Mathany, Timothy M. 0000-0002-4747-5113","orcid":"https://orcid.org/0000-0002-4747-5113","contributorId":99949,"corporation":false,"usgs":true,"family":"Mathany","given":"Timothy M.","affiliations":[],"preferred":false,"id":303311,"contributorType":{"id":1,"text":"Authors"},"rank":1},{"text":"Kulongoski, Justin T. 0000-0002-3498-4154","orcid":"https://orcid.org/0000-0002-3498-4154","contributorId":94750,"corporation":false,"usgs":true,"family":"Kulongoski","given":"Justin T.","affiliations":[],"preferred":false,"id":303310,"contributorType":{"id":1,"text":"Authors"},"rank":2},{"text":"Ray, Mary C.","contributorId":65945,"corporation":false,"usgs":true,"family":"Ray","given":"Mary","email":"","middleInitial":"C.","affiliations":[],"preferred":false,"id":303309,"contributorType":{"id":1,"text":"Authors"},"rank":3},{"text":"Belitz, Kenneth 0000-0003-4481-2345 kbelitz@usgs.gov","orcid":"https://orcid.org/0000-0003-4481-2345","contributorId":442,"corporation":false,"usgs":true,"family":"Belitz","given":"Kenneth","email":"kbelitz@usgs.gov","affiliations":[{"id":376,"text":"Massachusetts Water Science Center","active":true,"usgs":true},{"id":27111,"text":"National Water Quality Program","active":true,"usgs":true},{"id":466,"text":"New England Water Science Center","active":true,"usgs":true},{"id":451,"text":"National Water Quality Assessment Program","active":true,"usgs":true},{"id":503,"text":"Office of Water Quality","active":true,"usgs":true}],"preferred":true,"id":303308,"contributorType":{"id":1,"text":"Authors"},"rank":4}]}} ,{"id":97829,"text":"ds314 - 2009 - Selected ground-water-quality data in Pennsylvania - 1979-2006","interactions":[],"lastModifiedDate":"2017-06-22T08:33:24","indexId":"ds314","displayToPublicDate":"2009-09-17T00:00:00","publicationYear":"2009","noYear":false,"publicationType":{"id":18,"text":"Report"},"publicationSubtype":{"id":5,"text":"USGS Numbered Series"},"seriesTitle":{"id":310,"text":"Data Series","code":"DS","onlineIssn":"2327-638X","printIssn":"2327-0271","active":false,"publicationSubtype":{"id":5}},"seriesNumber":"314","title":"Selected ground-water-quality data in Pennsylvania - 1979-2006","docAbstract":"This study, by the U.S. Geological Survey (USGS) in cooperation with the Pennsylvania Department of Environmental Protection (PADEP), provides a compilation of ground-water-quality data for a 28-year period (January 1, 1979, through December 31, 2006) based on water samples from wells and springs. The data are from 14 source agencies or programs—Borough of Carroll Valley, Chester County Health Department, Montgomery County Health Department, Pennsylvania Department of Agriculture, Pennsylvania Department of Environmental Protection 2002 Pennsylvania Water-Quality Assessment, Pennsylvania Department of Environmental Protection Agency Act 537 Sewage Facilities Program, Pennsylvania Department of Environmental Protection-Ambient and Fixed Station Network, Pennsylvania Department of Environmental Protection–North-Central Region, Pennsylvania Department of Environmental Protection–South-Central Region, Pennsylvania Drinking Water Information System, Pennsylvania Topographic and Geologic Survey, Susquehanna River Basin Commission, U.S. Environmental Protection Agency, and the U.S. Geological Survey. The ground-water-quality data from the different source agencies or programs varied in type and number of analyses; however, the analyses are represented by 11 major analyte groups: antibiotics, major ions, microorganisms (bacteria, viruses, and other microorganisms), minor ions (including trace elements), nutrients (predominantly nitrate and nitrite as nitrogen), pesticides, pharmaceuticals, radiochemicals (predominantly radon or radium), volatiles (volatile organic compounds), wastewater compounds, and water characteristics (field measurements, predominantly field pH, field specific conductance, and hardness). For the USGS and the PADEP–North-Central Region, the pesticide analyte group was broken down into fungicides, herbicides, and insecticides.
Summary maps show the areal distribution of wells and springs with ground-water-quality data statewide by source agency or program. Summary data tables by source agency or program provide information on the number of wells and springs and samples collected for each of the 35 watersheds and analyte groups.
The number of wells and springs sampled for ground-water-quality data varies considerably across Pennsylvania. Of the 24,772 wells and springs sampled, the greatest concentration of wells and springs is in the southeast (Berks, Bucks, Chester, Delaware, Lancaster, Montgomery, and Philadelphia Counties) and in the northwest (Erie County). The number of wells and springs sampled is relatively sparse in north-central (Cameron, Elk, Forest, McKean, Potter, and Warren Counties) Pennsylvania. Little to no data are available for approximately one-fourth of the state. Nutrients and water characteristics were the most frequently sampled major analyte groups—43,025 and 30,583 samples, respectively. Minor ions and major ions were the next most frequently sampled major analyte groups–26,972 and 13,115 samples, respectively. For the remaining 10 major analyte groups, the number of samples collected ranged from a low of 24 samples (antibiotic compounds) to a high of approximately 4,674 samples (microorganisms).
The number of samples that exceeded a maximum contaminant level (MCL) or secondary maximum contaminant level (SMCL) by major analyte group also varied. Of the 4,674 samples in the microorganism analyte group, 50.2 percent had water that exceeded an MCL. Of the 4,528 samples collected and analyzed for volatile organic compounds, 23.5 percent exceeded an MCL. Other major analyte groups that frequently exceeded MCLs or SMCLs included major ions (18,343 samples and a 27.7 percent exceedence), minor ions (26,972 samples, 44.7 percent exceedence), pesticides (4,868 samples, 0.7 percent exceedence), water characteristics (30,583 samples, 19.3 percent exceedence), and radiochemicals (1,866 samples, 9.6 percent exceedence). Samples collected and analyzed for antibiotics (24 samples), fungicides (1,273 samples), herbicides (1,470 samples), insecticides (1,424 samples), nutrients (43,025 samples), pharmaceuticals (28 samples), and wastewater compounds (328 samples) had the lowest exceedences of 0.0, 2.4, 1.2, <1.0, 8.3, 0.0, and <1.0 percent, respectively.
A source- and finished-water-quality assessment of groundwater was conducted in the Piedmont Physiographic Province of Maryland and Virginia in the Potomac River Basin during 2003-04 as part of the U.S. Geological Survey's National Water-Quality Assessment Program. This assessment used a two-phased approach to sampling that allowed investigators to evaluate the occurrence of more than 280 anthropogenic organic compounds (volatile organic compounds, pesticides and pesticide degradates, and other anthropogenic organic compounds). Analysis of waters from 15 of the largest community water systems in the study area were included in the assessment. Source-water samples (raw-water samples collected prior to treatment) were collected at the well head. Finished-water samples (raw water that had been treated and disinfected) were collected after treatment and prior to distribution. Phase one samples, collected in August and September 2003, focused on source water. Phase two analyzed both source and finished water, and samples were collected in August and October of 2004. The results from phase one showed that samples collected from the source water for 15 community water systems contained 92 anthropogenic organic compounds (41 volatile organic compounds, 37 pesticides and pesticide degradates, and 14 other anthropogenic organic compounds). The 5 most frequently occurring anthropogenic organic compounds were detected in 11 of the 15 source-water samples. Deethylatrazine, a degradate of atrazine, was present in all 15 samples and metolachlor ethanesulfonic acid, a degradate of metolachlor, and chloroform were present in 13 samples. Atrazine and metolachlor were present in 12 and 11 samples, respectively. All samples contained a mixture of compounds with an average of about 14 compounds per sample. Phase two sampling focused on 10 of the 15 community water systems that were selected for resampling on the basis of occurrence of anthropogenic organic compounds detected most frequently during the first phase. A total of 48 different anthropogenic organic compounds were detected in samples collected from source and finished water. There were a similar number of compounds detected in finished water (41) and in source water (39). The most commonly detected group of anthropogenic organic compounds in finished water was trihalomethanes - compounds associated with the disinfection of drinking water. This group of compounds accounted for 30 percent of the detections in source water and 44 percent of the detections in finished water, and were generally found in higher concentrations in finished water. Excluding trihalomethanes, the number of total detections was about the same in source-water samples (33) as it was in finished-water samples (35). During both phases of the study, two measurements for human-health assessment were used. The first, the Maximum Contaminant Level for drinking water, is set by the U.S. Environmental Protection Agency and represents a legally enforceable maximum concentration of a contaminant permitted in drinking water. The second, the Health-Based Screening Level, was developed by the U.S. Geological Survey, is not legally enforceable, and represents a limit for more chronic exposures. Maximum concentrations for each detected compound were compared with either the Maximum Contaminant Level or the Health-Based Screening Level when available. More than half of the compounds detected had either a Maximum Contaminant Level or a Health-Based Screening Level. A benchmark quotient was set at 10 percent (greater than or equal to 0.1) of the ratio of the detected concentration of a particular compound to its Maximum Contaminant Level, or Health-Based Screening Level. This was considered a threshold for further monitoring. During phase one, when only source water was sampled, seven compounds (chloroform, benzene, acrylonitrile, methylene chloride, atrazine, alachlor, and dieldrin) met or exceeded a benchmark quotient.
","language":"English","publisher":"U.S. Geological Survey","doi":"10.3133/sir20095064","usgsCitation":"Banks, W.S., and Reyes, B., 2009, Anthropogenic organic compounds in source and finished groundwater of community water systems in the Piedmont Physiographic Province, Potomac River Basin, Maryland and Virginia, 2003-04: U.S. Geological Survey Scientific Investigations Report 2009-5064, viii, 33 p., https://doi.org/10.3133/sir20095064.","productDescription":"viii, 33 p.","temporalStart":"2003-01-01","temporalEnd":"2004-12-31","costCenters":[{"id":41514,"text":"Maryland-Delaware-District of Columbia Water Science Center","active":true,"usgs":true}],"links":[{"id":118623,"rank":1,"type":{"id":24,"text":"Thumbnail"},"url":"https://pubs.usgs.gov/thumbnails/sir_2009_5064.jpg"},{"id":415377,"rank":3,"type":{"id":36,"text":"NGMDB Index Page"},"url":"https://ngmdb.usgs.gov/Prodesc/proddesc_87077.htm","linkFileType":{"id":5,"text":"html"}},{"id":12929,"rank":2,"type":{"id":15,"text":"Index Page"},"url":"https://pubs.usgs.gov/sir/2009/5064/","linkFileType":{"id":5,"text":"html"}}],"country":"United States","state":"Maryland, Virginia","otherGeospatial":"Piedmont Physiographic Province, Potomac River Basin","geographicExtents":"{\n \"type\": \"FeatureCollection\",\n \"features\": [\n {\n \"type\": \"Feature\",\n \"properties\": {},\n \"geometry\": {\n \"type\": \"Polygon\",\n \"coordinates\": [\n [\n [\n -78.0833,\n 39.7167\n ],\n [\n -78.0833,\n 38.4167\n ],\n [\n -77,\n 38.4167\n ],\n [\n -77,\n 39.7167\n ],\n [\n -78.0833,\n 39.7167\n ]\n ]\n ]\n }\n }\n ]\n}","noUsgsAuthors":false,"publicationStatus":"PW","scienceBaseUri":"4f4e4ac8e4b07f02db67b735","contributors":{"authors":[{"text":"Banks, William S.L.","contributorId":35281,"corporation":false,"usgs":true,"family":"Banks","given":"William","email":"","middleInitial":"S.L.","affiliations":[],"preferred":false,"id":303075,"contributorType":{"id":1,"text":"Authors"},"rank":1},{"text":"Reyes, Betzaida 0000-0002-1398-0824 breyes@usgs.gov","orcid":"https://orcid.org/0000-0002-1398-0824","contributorId":2250,"corporation":false,"usgs":true,"family":"Reyes","given":"Betzaida","email":"breyes@usgs.gov","affiliations":[{"id":374,"text":"Maryland Water Science Center","active":true,"usgs":true}],"preferred":true,"id":303074,"contributorType":{"id":1,"text":"Authors"},"rank":2}]}} ,{"id":97771,"text":"ds461 - 2009 - Probability of Elevated Volatile Organic Compound (VOC) Concentrations in Groundwater in the Eagle River Watershed Valley-Fill Aquifer, Eagle County, North-Central Colorado, 2006-2007","interactions":[],"lastModifiedDate":"2018-03-21T15:13:05","indexId":"ds461","displayToPublicDate":"2009-08-18T00:00:00","publicationYear":"2009","noYear":false,"publicationType":{"id":18,"text":"Report"},"publicationSubtype":{"id":5,"text":"USGS Numbered Series"},"seriesTitle":{"id":310,"text":"Data Series","code":"DS","onlineIssn":"2327-638X","printIssn":"2327-0271","active":false,"publicationSubtype":{"id":5}},"seriesNumber":"461","title":"Probability of Elevated Volatile Organic Compound (VOC) Concentrations in Groundwater in the Eagle River Watershed Valley-Fill Aquifer, Eagle County, North-Central Colorado, 2006-2007","docAbstract":"This raster data set delineates the predicted probability of elevated volatile organic compound (VOC) concentrations in groundwater in the Eagle River watershed valley-fill aquifer, Eagle County, North-Central Colorado, 2006-2007. This data set was developed by a cooperative project between the U.S. Geological Survey, Eagle County, the Eagle River Water and Sanitation District, the Town of Eagle, the Town of Gypsum, and the Upper Eagle Regional Water Authority. This project was designed to evaluate potential land-development effects on groundwater and surface-water resources so that informed land-use and water management decisions can be made. This groundwater probability map and its associated probability maps was developed as follows: (1) A point data set of wells with groundwater quality and groundwater age data was overlaid with thematic layers of anthropogenic (related to human activities) and hydrogeologic data by using a geographic information system to assign each well values for depth to groundwater, distance to major streams and canals, distance to gypsum beds, precipitation, soils, and well depth. These data then were downloaded to a statistical software package for analysis by logistic regression. (2) Statistical models predicting the probability of elevated nitrate concentrations, the probability of unmixed young water (using chlorofluorocarbon-11 concentrations and tritium activities), and the probability of elevated volatile organic compound concentrations were developed using logistic regression techniques. (3) The statistical models were entered into a GIS and the probability map was constructed.","language":"ENGLISH","publisher":"U.S. Geological Survey","doi":"10.3133/ds461","usgsCitation":"Rupert, M.G., and Plummer, N., 2009, Probability of Elevated Volatile Organic Compound (VOC) Concentrations in Groundwater in the Eagle River Watershed Valley-Fill Aquifer, Eagle County, North-Central Colorado, 2006-2007: U.S. Geological Survey Data Series 461, Available online only, https://doi.org/10.3133/ds461.","productDescription":"Available online only","onlineOnly":"Y","additionalOnlineFiles":"Y","temporalStart":"2006-01-01","temporalEnd":"2007-12-31","costCenters":[{"id":191,"text":"Colorado Water Science Center","active":true,"usgs":true}],"links":[{"id":196258,"rank":0,"type":{"id":24,"text":"Thumbnail"},"url":"https://pubs.usgs.gov/thumbnails/usgs_thumb.jpg"},{"id":12942,"rank":100,"type":{"id":15,"text":"Index Page"},"url":"https://pubs.usgs.gov/ds/461/","linkFileType":{"id":5,"text":"html"}}],"noUsgsAuthors":false,"publicationStatus":"PW","scienceBaseUri":"4f4e4a9ee4b07f02db660c29","contributors":{"authors":[{"text":"Rupert, Michael G. mgrupert@usgs.gov","contributorId":1194,"corporation":false,"usgs":true,"family":"Rupert","given":"Michael","email":"mgrupert@usgs.gov","middleInitial":"G.","affiliations":[{"id":191,"text":"Colorado Water Science Center","active":true,"usgs":true}],"preferred":true,"id":303103,"contributorType":{"id":1,"text":"Authors"},"rank":1},{"text":"Plummer, Niel 0000-0002-4020-1013 nplummer@usgs.gov","orcid":"https://orcid.org/0000-0002-4020-1013","contributorId":190100,"corporation":false,"usgs":true,"family":"Plummer","given":"Niel","email":"nplummer@usgs.gov","affiliations":[{"id":436,"text":"National Research Program - Eastern Branch","active":true,"usgs":true}],"preferred":true,"id":303104,"contributorType":{"id":1,"text":"Authors"},"rank":2}]}} ,{"id":97769,"text":"ds459 - 2009 - Probability of Elevated Nitrate Concentrations in Groundwater in the Eagle River Watershed Valley-Fill Aquifer, Eagle County, North-Central Colorado, 2006-2007","interactions":[],"lastModifiedDate":"2018-03-21T15:13:58","indexId":"ds459","displayToPublicDate":"2009-08-18T00:00:00","publicationYear":"2009","noYear":false,"publicationType":{"id":18,"text":"Report"},"publicationSubtype":{"id":5,"text":"USGS Numbered Series"},"seriesTitle":{"id":310,"text":"Data Series","code":"DS","onlineIssn":"2327-638X","printIssn":"2327-0271","active":false,"publicationSubtype":{"id":5}},"seriesNumber":"459","title":"Probability of Elevated Nitrate Concentrations in Groundwater in the Eagle River Watershed Valley-Fill Aquifer, Eagle County, North-Central Colorado, 2006-2007","docAbstract":"This raster data set delineates the predicted probability of elevated nitrate concentrations in groundwater in the Eagle River watershed valley-fill aquifer, Eagle County, North-Central Colorado, 2006-2007. This data set was developed by a cooperative project between the U.S. Geological Survey, Eagle County, the Eagle River Water and Sanitation District, the Town of Eagle, the Town of Gypsum, and the Upper Eagle Regional Water Authority. This project was designed to evaluate potential land-development effects on groundwater and surface-water resources so that informed land-use and water management decisions can be made. This groundwater probability map and its associated probability maps was developed as follows: (1) A point data set of wells with groundwater quality and groundwater age data was overlaid with thematic layers of anthropogenic (related to human activities) and hydrogeologic data by using a geographic information system to assign each well values for depth to groundwater, distance to major streams and canals, distance to gypsum beds, precipitation, soils, and well depth. These data then were downloaded to a statistical software package for analysis by logistic regression. (2) Statistical models predicting the probability of elevated nitrate concentrations, the probability of unmixed young water (using chlorofluorocarbon-11 concentrations and tritium activities), and the probability of elevated volatile organic compound concentrations were developed using logistic regression techniques. (3) The statistical models were entered into a GIS and the probability map was constructed.","language":"ENGLISH","publisher":"U.S. Geological Survey","doi":"10.3133/ds459","usgsCitation":"Rupert, M.G., and Plummer, N., 2009, Probability of Elevated Nitrate Concentrations in Groundwater in the Eagle River Watershed Valley-Fill Aquifer, Eagle County, North-Central Colorado, 2006-2007: U.S. Geological Survey Data Series 459, Available online only, https://doi.org/10.3133/ds459.","productDescription":"Available online only","onlineOnly":"Y","additionalOnlineFiles":"Y","temporalStart":"2006-01-01","temporalEnd":"2007-12-31","costCenters":[{"id":191,"text":"Colorado Water Science Center","active":true,"usgs":true}],"links":[{"id":198307,"rank":0,"type":{"id":24,"text":"Thumbnail"},"url":"https://pubs.usgs.gov/thumbnails/usgs_thumb.jpg"},{"id":12940,"rank":100,"type":{"id":15,"text":"Index Page"},"url":"https://pubs.usgs.gov/ds/459/","linkFileType":{"id":5,"text":"html"}},{"id":13973,"rank":200,"type":{"id":11,"text":"Document"},"url":"https://water.usgs.gov/GIS/metadata/usgswrd/XML/sir095082_no3.xml","linkFileType":{"id":5,"text":"html"}}],"noUsgsAuthors":false,"publicationStatus":"PW","scienceBaseUri":"4f4e4a9ee4b07f02db660b7f","contributors":{"authors":[{"text":"Rupert, Michael G. mgrupert@usgs.gov","contributorId":1194,"corporation":false,"usgs":true,"family":"Rupert","given":"Michael","email":"mgrupert@usgs.gov","middleInitial":"G.","affiliations":[{"id":191,"text":"Colorado Water Science Center","active":true,"usgs":true}],"preferred":true,"id":303099,"contributorType":{"id":1,"text":"Authors"},"rank":1},{"text":"Plummer, Niel 0000-0002-4020-1013 nplummer@usgs.gov","orcid":"https://orcid.org/0000-0002-4020-1013","contributorId":190100,"corporation":false,"usgs":true,"family":"Plummer","given":"Niel","email":"nplummer@usgs.gov","affiliations":[{"id":436,"text":"National Research Program - Eastern Branch","active":true,"usgs":true}],"preferred":true,"id":303100,"contributorType":{"id":1,"text":"Authors"},"rank":2}]}} ,{"id":97767,"text":"sir20095161 - 2009 - Source, Transport, and Fate of Groundwater Contamination at Site 45, Marine Corps Recruit Depot, Parris Island, South Carolina","interactions":[],"lastModifiedDate":"2017-01-17T10:22:15","indexId":"sir20095161","displayToPublicDate":"2009-08-18T00:00:00","publicationYear":"2009","noYear":false,"publicationType":{"id":18,"text":"Report"},"publicationSubtype":{"id":5,"text":"USGS Numbered Series"},"seriesTitle":{"id":334,"text":"Scientific Investigations Report","code":"SIR","onlineIssn":"2328-0328","printIssn":"2328-031X","active":true,"publicationSubtype":{"id":5}},"seriesNumber":"2009-5161","title":"Source, Transport, and Fate of Groundwater Contamination at Site 45, Marine Corps Recruit Depot, Parris Island, South Carolina","docAbstract":"Groundwater contamination by tetrachloroethene and its dechlorination products is present in two partially intermingled plumes in the surficial aquifer near a former dry-cleaning facility at Site 45, Marine Corps Recruit Depot, Parris Island, South Carolina. The northern plume originates from the vicinity of former above-ground storage tanks. Free-phase tetrachloroethene from activities in this area entered the groundwater and the storm sewer. The southern plume originates at a nearby new dry-cleaning facility, but probably was the result of contamination released to the aquifer from a leaking sanitary sewer line from the former dry-cleaning facility. Discharge of dissolved groundwater contamination is primarily to leaking storm sewers below the water table. Extensive biodegradation of the contamination takes place in the surficial aquifer; however, the biodegradation is insufficient to reduce trichloroethene to less than milligram-per-liter concentrations prior to discharging into the storm sewers. The groundwater volatile organic compounds entering the storm sewers are substantially diluted by tidal flushing upon entry and are subject to volatilization as they are transported through the storm sewer to a discharge point in a tributary to Ballast Creek. TCE concentrations of about 2-6 micrograms per liter were present in storm-sewer water near the discharge point (sampled at manhole STS26). On three out of four sampling events at manhole STS14, the storm-sewer water contained no vinyl chloride. During a time of relatively high groundwater levels, however, 20 micrograms per liter of vinyl chloride was present in STS14 storm-sewer water. Because groundwater leaks into that storm sewer and because the storm sewer upgradient from manhole STS14 is adjacent to part of the aquifer where 2,290 micrograms per liter of vinyl chloride have been detected, there is a potential for substantially increased concentrations of vinyl chloride to discharge at the storm-sewer outfall under conditions of high groundwater levels and low tidal flushing. In addition, the observation that free-phase tetrachloroethene may have entered the storm-sewer system during the 1994 discharge means that dense nonaqueous phase liquid tetrachloroethene could have leaked from various parts of the storm sewer or discharged to surface water at the storm-sewer outfall.","language":"ENGLISH","publisher":"U.S. Geological Survey","doi":"10.3133/sir20095161","collaboration":"Prepared in cooperation with the Naval Facilities Engineering Command Southeast","usgsCitation":"Vroblesky, D.A., Petkewich, M.D., Landmeyer, J., and Lowery, M.A., 2009, Source, Transport, and Fate of Groundwater Contamination at Site 45, Marine Corps Recruit Depot, Parris Island, South Carolina: U.S. Geological Survey Scientific Investigations Report 2009-5161, viii, 80 p., https://doi.org/10.3133/sir20095161.","productDescription":"viii, 80 p.","costCenters":[{"id":13634,"text":"South Atlantic Water Science Center","active":true,"usgs":true}],"links":[{"id":125619,"rank":0,"type":{"id":24,"text":"Thumbnail"},"url":"https://pubs.usgs.gov/thumbnails/sir_2009_5161.jpg"},{"id":12934,"rank":100,"type":{"id":15,"text":"Index Page"},"url":"https://pubs.usgs.gov/sir/2009/5161/","linkFileType":{"id":5,"text":"html"}}],"country":"United States","state":"South Carolina","otherGeospatial":"Marine Corp Recruit Depot, Parris Island","geographicExtents":"{ \"type\": \"FeatureCollection\", \"features\": [ { \"type\": \"Feature\", \"properties\": {}, \"geometry\": { \"type\": \"Polygon\", \"coordinates\": [ [ [ -80.75027777777778,32.284166666666664 ], [ -80.75027777777778,32.38333333333333 ], [ -80.65,32.38333333333333 ], [ -80.65,32.284166666666664 ], [ -80.75027777777778,32.284166666666664 ] ] ] } } ] }","noUsgsAuthors":false,"publicationStatus":"PW","scienceBaseUri":"4f4e4afee4b07f02db69782a","contributors":{"authors":[{"text":"Vroblesky, Don A. vroblesk@usgs.gov","contributorId":413,"corporation":false,"usgs":true,"family":"Vroblesky","given":"Don","email":"vroblesk@usgs.gov","middleInitial":"A.","affiliations":[],"preferred":true,"id":303093,"contributorType":{"id":1,"text":"Authors"},"rank":1},{"text":"Petkewich, Matthew D. 0000-0002-5749-6356 mdpetkew@usgs.gov","orcid":"https://orcid.org/0000-0002-5749-6356","contributorId":982,"corporation":false,"usgs":true,"family":"Petkewich","given":"Matthew","email":"mdpetkew@usgs.gov","middleInitial":"D.","affiliations":[{"id":13634,"text":"South Atlantic Water Science Center","active":true,"usgs":true},{"id":559,"text":"South Carolina Water Science Center","active":true,"usgs":true}],"preferred":true,"id":303094,"contributorType":{"id":1,"text":"Authors"},"rank":2},{"text":"Landmeyer, James 0000-0002-5640-3816 jlandmey@usgs.gov","orcid":"https://orcid.org/0000-0002-5640-3816","contributorId":3257,"corporation":false,"usgs":true,"family":"Landmeyer","given":"James","email":"jlandmey@usgs.gov","affiliations":[{"id":13634,"text":"South Atlantic Water Science Center","active":true,"usgs":true}],"preferred":true,"id":303095,"contributorType":{"id":1,"text":"Authors"},"rank":3},{"text":"Lowery, Mark A.","contributorId":77872,"corporation":false,"usgs":true,"family":"Lowery","given":"Mark","email":"","middleInitial":"A.","affiliations":[],"preferred":false,"id":303096,"contributorType":{"id":1,"text":"Authors"},"rank":4}]}} ,{"id":97770,"text":"ds460 - 2009 - Probability of Unmixed Young Groundwater (defined using chlorofluorocarbon-11 concentrations and tritium activities) in the Eagle River Watershed Valley-Fill Aquifer, Eagle County, North-Central Colorado, 2006-2007","interactions":[],"lastModifiedDate":"2018-03-21T15:13:37","indexId":"ds460","displayToPublicDate":"2009-08-18T00:00:00","publicationYear":"2009","noYear":false,"publicationType":{"id":18,"text":"Report"},"publicationSubtype":{"id":5,"text":"USGS Numbered Series"},"seriesTitle":{"id":310,"text":"Data Series","code":"DS","onlineIssn":"2327-638X","printIssn":"2327-0271","active":false,"publicationSubtype":{"id":5}},"seriesNumber":"460","title":"Probability of Unmixed Young Groundwater (defined using chlorofluorocarbon-11 concentrations and tritium activities) in the Eagle River Watershed Valley-Fill Aquifer, Eagle County, North-Central Colorado, 2006-2007","docAbstract":"This raster data set delineates the predicted probability of unmixed young groundwater (defined using chlorofluorocarbon-11 concentrations and tritium activities) in groundwater in the Eagle River watershed valley-fill aquifer, Eagle County, North-Central Colorado, 2006-2007. This data set was developed by a cooperative project between the U.S. Geological Survey, Eagle County, the Eagle River Water and Sanitation District, the Town of Eagle, the Town of Gypsum, and the Upper Eagle Regional Water Authority. This project was designed to evaluate potential land-development effects on groundwater and surface-water resources so that informed land-use and water management decisions can be made. This groundwater probability map and its associated probability maps were developed as follows: (1) A point data set of wells with groundwater quality and groundwater age data was overlaid with thematic layers of anthropogenic (related to human activities) and hydrogeologic data by using a geographic information system to assign each well values for depth to groundwater, distance to major streams and canals, distance to gypsum beds, precipitation, soils, and well depth. These data then were downloaded to a statistical software package for analysis by logistic regression. (2) Statistical models predicting the probability of elevated nitrate concentrations, the probability of unmixed young water (using chlorofluorocarbon-11 concentrations and tritium activities), and the probability of elevated volatile organic compound concentrations were developed using logistic regression techniques. (3) The statistical models were entered into a GIS and the probability map was constructed.","language":"ENGLISH","publisher":"U.S. Geological Survey","doi":"10.3133/ds460","usgsCitation":"Rupert, M.G., and Plummer, N., 2009, Probability of Unmixed Young Groundwater (defined using chlorofluorocarbon-11 concentrations and tritium activities) in the Eagle River Watershed Valley-Fill Aquifer, Eagle County, North-Central Colorado, 2006-2007: U.S. Geological Survey Data Series 460, Available online only, https://doi.org/10.3133/ds460.","productDescription":"Available online only","onlineOnly":"Y","additionalOnlineFiles":"Y","temporalStart":"2006-01-01","temporalEnd":"2007-12-31","costCenters":[{"id":191,"text":"Colorado Water Science Center","active":true,"usgs":true}],"links":[{"id":198338,"rank":0,"type":{"id":24,"text":"Thumbnail"},"url":"https://pubs.usgs.gov/thumbnails/usgs_thumb.jpg"},{"id":12941,"rank":100,"type":{"id":15,"text":"Index Page"},"url":"https://pubs.usgs.gov/ds/460/","linkFileType":{"id":5,"text":"html"}}],"noUsgsAuthors":false,"publicationStatus":"PW","scienceBaseUri":"4f4e4a9ee4b07f02db660c44","contributors":{"authors":[{"text":"Rupert, Michael G. mgrupert@usgs.gov","contributorId":1194,"corporation":false,"usgs":true,"family":"Rupert","given":"Michael","email":"mgrupert@usgs.gov","middleInitial":"G.","affiliations":[{"id":191,"text":"Colorado Water Science Center","active":true,"usgs":true}],"preferred":true,"id":303101,"contributorType":{"id":1,"text":"Authors"},"rank":1},{"text":"Plummer, Niel 0000-0002-4020-1013 nplummer@usgs.gov","orcid":"https://orcid.org/0000-0002-4020-1013","contributorId":190100,"corporation":false,"usgs":true,"family":"Plummer","given":"Niel","email":"nplummer@usgs.gov","affiliations":[{"id":436,"text":"National Research Program - Eastern Branch","active":true,"usgs":true}],"preferred":true,"id":303102,"contributorType":{"id":1,"text":"Authors"},"rank":2}]}} ,{"id":97707,"text":"sir20095082 - 2009 - Groundwater quality, age, and probability of contamination, Eagle River watershed valley-fill aquifer, north-central Colorado, 2006-2007","interactions":[],"lastModifiedDate":"2019-08-15T11:52:21","indexId":"sir20095082","displayToPublicDate":"2009-07-25T00:00:00","publicationYear":"2009","noYear":false,"publicationType":{"id":18,"text":"Report"},"publicationSubtype":{"id":5,"text":"USGS Numbered Series"},"seriesTitle":{"id":334,"text":"Scientific Investigations Report","code":"SIR","onlineIssn":"2328-0328","printIssn":"2328-031X","active":true,"publicationSubtype":{"id":5}},"seriesNumber":"2009-5082","title":"Groundwater quality, age, and probability of contamination, Eagle River watershed valley-fill aquifer, north-central Colorado, 2006-2007","docAbstract":"The Eagle River watershed is located near the destination resort town of Vail, Colorado. The area has a fastgrowing permanent population, and the resort industry is rapidly expanding. A large percentage of the land undergoing development to support that growth overlies the Eagle River watershed valley-fill aquifer (ERWVFA), which likely has a high predisposition to groundwater contamination. As development continues, local organizations need tools to evaluate potential land-development effects on ground- and surface-water resources so that informed land-use and water management decisions can be made. To help develop these tools, the U.S. Geological Survey (USGS), in cooperation with Eagle County, the Eagle River Water and Sanitation District, the Town of Eagle, the Town of Gypsum, and the Upper Eagle Regional Water Authority, conducted a study in 2006-2007 of the groundwater quality, age, and probability of contamination in the ERWVFA, north-central Colorado.\r\n\r\nGround- and surface-water quality samples were analyzed for major ions, nutrients, stable isotopes of hydrogen and oxygen in water, tritium, dissolved gases, chlorofluorocarbons (CFCs), and volatile organic compounds (VOCs) determined with very low-level laboratory methods. The major-ion data indicate that groundwaters in the ERWVFA can be classified into two major groups: groundwater that was recharged by infiltration of surface water, and groundwater that had less immediate recharge from surface water and had elevated sulfate concentrations. Sulfate concentrations exceeded the USEPA National Secondary Drinking Water Regulations (250 milligrams per liter) in many wells near Eagle, Gypsum, and Dotsero. The predominant source of sulfate to groundwater in the Eagle River watershed is the Eagle Valley Evaporite, which is a gypsum deposit of Pennsylvanian age located predominantly in the western one-half of Eagle County.","language":"English","publisher":"U.S. Geological Survey","publisherLocation":"Reston, VA","doi":"10.3133/sir20095082","isbn":"9781411324879","collaboration":"Prepared in cooperation with Eagle County, the Eagle River Water and Sanitation District, the Town of Eagle, the Town of Gypsum, and the Upper Eagle Regional Water Authority","usgsCitation":"Rupert, M.G., and Plummer, N., 2009, Groundwater quality, age, and probability of contamination, Eagle River watershed valley-fill aquifer, north-central Colorado, 2006-2007: U.S. Geological Survey Scientific Investigations Report 2009-5082, viii, 59 p., https://doi.org/10.3133/sir20095082.","productDescription":"viii, 59 p.","temporalStart":"2006-01-01","temporalEnd":"2007-12-31","costCenters":[{"id":191,"text":"Colorado Water Science Center","active":true,"usgs":true},{"id":589,"text":"Toxic Substances Hydrology Program","active":true,"usgs":true}],"links":[{"id":118629,"rank":0,"type":{"id":24,"text":"Thumbnail"},"url":"https://pubs.usgs.gov/thumbnails/sir_2009_5082.jpg"},{"id":12862,"rank":100,"type":{"id":15,"text":"Index Page"},"url":"https://pubs.usgs.gov/sir/2009/5082/","linkFileType":{"id":5,"text":"html"}}],"country":"United States","state":"Colorado","geographicExtents":"{ \"type\": \"FeatureCollection\", \"features\": [ { \"type\": \"Feature\", \"properties\": {}, \"geometry\": { \"type\": \"Polygon\", \"coordinates\": [ [ [ -107.16666666666667,39.333333333333336 ], [ -107.16666666666667,40 ], [ -106,40 ], [ -106,39.333333333333336 ], [ -107.16666666666667,39.333333333333336 ] ] ] } } ] }","noUsgsAuthors":false,"publicationStatus":"PW","scienceBaseUri":"4f4e4878e4b07f02db510f5f","contributors":{"authors":[{"text":"Rupert, Michael G. mgrupert@usgs.gov","contributorId":1194,"corporation":false,"usgs":true,"family":"Rupert","given":"Michael","email":"mgrupert@usgs.gov","middleInitial":"G.","affiliations":[{"id":191,"text":"Colorado Water Science Center","active":true,"usgs":true}],"preferred":true,"id":302946,"contributorType":{"id":1,"text":"Authors"},"rank":1},{"text":"Plummer, Niel 0000-0002-4020-1013 nplummer@usgs.gov","orcid":"https://orcid.org/0000-0002-4020-1013","contributorId":190100,"corporation":false,"usgs":true,"family":"Plummer","given":"Niel","email":"nplummer@usgs.gov","affiliations":[{"id":436,"text":"National Research Program - Eastern Branch","active":true,"usgs":true}],"preferred":true,"id":302947,"contributorType":{"id":1,"text":"Authors"},"rank":2}]}} ,{"id":97692,"text":"sir20085243 - 2009 - Occurrence of Selected Organic Compounds in Groundwater Used for Public Supply in the Plio-Pleistocene Deposits in East-Central Nebraska and the Dawson and Denver Aquifers near Denver, Colorado, 2002-2004","interactions":[],"lastModifiedDate":"2012-03-02T17:16:07","indexId":"sir20085243","displayToPublicDate":"2009-07-17T00:00:00","publicationYear":"2009","noYear":false,"publicationType":{"id":18,"text":"Report"},"publicationSubtype":{"id":5,"text":"USGS Numbered Series"},"seriesTitle":{"id":334,"text":"Scientific Investigations Report","code":"SIR","onlineIssn":"2328-0328","printIssn":"2328-031X","active":true,"publicationSubtype":{"id":5}},"seriesNumber":"2008-5243","title":"Occurrence of Selected Organic Compounds in Groundwater Used for Public Supply in the Plio-Pleistocene Deposits in East-Central Nebraska and the Dawson and Denver Aquifers near Denver, Colorado, 2002-2004","docAbstract":"The National Water-Quality Assessment Program of the U.S. Geological Survey has an ongoing Source Water-Quality Assessment program designed to characterize the quality of water in aquifers used as a source of drinking-water supply for some of the largest metropolitan areas in the Nation. In addition to the sampling of the source waters, sampling of finished or treated waters was done in the second year of local studies to evaluate if the organic compounds detected in the source waters also were present in the water supplied to the public.\r\n\r\nAn evaluation of source-water quality used in selected groundwater-supplied public water systems in east-central Nebraska and in the south Denver metropolitan area of Colorado was completed during 2002 through 2004. Fifteen wells in the Plio-Pleistocene alluvial and glacial deposits in east-central Nebraska (the High Plains study) and 12 wells in the Dawson and Denver aquifers, south of Denver (the South Platte study), were sampled during the first year to obtain information on the occurrence and distribution of selected organic chemicals in the source waters. During the second year of the study, two wells in east-central Nebraska were resampled, along with the associated finished water derived from these wells, to determine if organic compounds detected in the source water also were present in the finished water. Selection of the second-phase sampling sites was based on detections of the most-frequently occurring organic compounds from the first-year Source Water-Quality Assessment study results. The second-year sampling also required that finished waters had undergone water-quality treatment processes before being distributed to the public.\r\n\r\nSample results from the first year of sampling groundwater wells in east-central Nebraska show that the most-frequently detected organic compounds were the pesticide atrazine and its degradate, deethylatrazine (DEA, otherwise known as 2-chloro-4-isopropylamino-6-amino-s-triazine or CIAT), which were detected in 9 of the 15 wells (60 percent of the samples). The second most frequently detected organic compound was tetrachloroethylene, detected in 4 of the 15 wells (27 percent of the samples), followed by chloroform, trichloroethylene, and 2-hydroxyatrazine (2-hydroxy-4-isopropylamino-6-ethylamino-s-triazine, or OIET), present in 3 of the 15 wells (20 percent of the samples). The pesticide compounds deisopropylatrazine (2-chloro-6-ethylamino-4-amino-s-triazine, or CEAT), metolachlor, and simazine and the volatile organic compound cis-1,2-dichloroethylene were detected in 2 of the 15 wells, and the compounds diuron and 1,2-dichloroethane were detected in only 1 of the 15 wells during the first-year sampling. Most detections of these compounds were at or near the minimum reporting levels, and none were greater than their regulatory maximum contaminant level.\r\n\r\nThere were few detections of organic compounds during the first year of sampling groundwater wells in the South Platte study area. The compounds atrazine, deethylatrazine, picloram, tetrachloroethylene, methyl-tert-butyl-ether (MTBE), tris(2-butoxyethyl)phosphate, and bromoform were detected only once in all the samples from the 12 wells. Most detections of these compounds were at or near the minimum reporting levels, and none were greater than their regulatory maximum contaminant level.\r\n\r\nSecond-year sampling, which included the addition of paired source- and finished-water samples, was completed at two sites in the High Plains study area. Source-water samples from the second-year sampling had detections of atrazine and deethylatrazine; at one site deisopropylatrazine and chloroform also were detected. The finished-water samples, which represent the source water after blending with water from other wells and treatment, indicated a decrease in the concentrations of the pesticides at one site, whereas concentrations remained nearly constant at a second site. The trihalomethanes (THMs or disinfec","language":"ENGLISH","publisher":"U.S. Geological Survey","doi":"10.3133/sir20085243","isbn":"9781411325135","usgsCitation":"Bails, J.B., Dietsch, B.J., Landon, M.K., and Paschke, S.S., 2009, Occurrence of Selected Organic Compounds in Groundwater Used for Public Supply in the Plio-Pleistocene Deposits in East-Central Nebraska and the Dawson and Denver Aquifers near Denver, Colorado, 2002-2004: U.S. Geological Survey Scientific Investigations Report 2008-5243, viii, 30 p., https://doi.org/10.3133/sir20085243.","productDescription":"viii, 30 p.","costCenters":[{"id":191,"text":"Colorado Water Science Center","active":true,"usgs":true}],"links":[{"id":118625,"rank":0,"type":{"id":24,"text":"Thumbnail"},"url":"https://pubs.usgs.gov/thumbnails/sir_2008_5243.jpg"},{"id":12847,"rank":100,"type":{"id":15,"text":"Index Page"},"url":"https://pubs.usgs.gov/sir/2008/5243/","linkFileType":{"id":5,"text":"html"}}],"noUsgsAuthors":false,"publicationStatus":"PW","scienceBaseUri":"4f4e4a80e4b07f02db6493dc","contributors":{"authors":[{"text":"Bails, Jeffrey B. jbbails@usgs.gov","contributorId":813,"corporation":false,"usgs":true,"family":"Bails","given":"Jeffrey","email":"jbbails@usgs.gov","middleInitial":"B.","affiliations":[],"preferred":true,"id":302899,"contributorType":{"id":1,"text":"Authors"},"rank":1},{"text":"Dietsch, Benjamin J. 0000-0003-1090-409X bdietsch@usgs.gov","orcid":"https://orcid.org/0000-0003-1090-409X","contributorId":1346,"corporation":false,"usgs":true,"family":"Dietsch","given":"Benjamin","email":"bdietsch@usgs.gov","middleInitial":"J.","affiliations":[{"id":464,"text":"Nebraska Water Science Center","active":true,"usgs":true}],"preferred":true,"id":302900,"contributorType":{"id":1,"text":"Authors"},"rank":2},{"text":"Landon, Matthew K. 0000-0002-5766-0494 landon@usgs.gov","orcid":"https://orcid.org/0000-0002-5766-0494","contributorId":392,"corporation":false,"usgs":true,"family":"Landon","given":"Matthew","email":"landon@usgs.gov","middleInitial":"K.","affiliations":[{"id":154,"text":"California Water Science Center","active":true,"usgs":true}],"preferred":true,"id":302898,"contributorType":{"id":1,"text":"Authors"},"rank":3},{"text":"Paschke, Suzanne S.","contributorId":14072,"corporation":false,"usgs":true,"family":"Paschke","given":"Suzanne","email":"","middleInitial":"S.","affiliations":[],"preferred":false,"id":302901,"contributorType":{"id":1,"text":"Authors"},"rank":4}]}} ,{"id":97688,"text":"sir20095091 - 2009 - Quality of Shallow Groundwater and Drinking Water in the Mississippi Embayment-Texas Coastal Uplands Aquifer System and the Mississippi River Valley Alluvial Aquifer, South-Central United States, 1994-2004","interactions":[],"lastModifiedDate":"2012-03-08T17:16:27","indexId":"sir20095091","displayToPublicDate":"2009-07-17T00:00:00","publicationYear":"2009","noYear":false,"publicationType":{"id":18,"text":"Report"},"publicationSubtype":{"id":5,"text":"USGS Numbered Series"},"seriesTitle":{"id":334,"text":"Scientific Investigations Report","code":"SIR","onlineIssn":"2328-0328","printIssn":"2328-031X","active":true,"publicationSubtype":{"id":5}},"seriesNumber":"2009-5091","title":"Quality of Shallow Groundwater and Drinking Water in the Mississippi Embayment-Texas Coastal Uplands Aquifer System and the Mississippi River Valley Alluvial Aquifer, South-Central United States, 1994-2004","docAbstract":"The Mississippi embayment-Texas coastal uplands aquifer system is an important source of drinking water, providing about 724 million gallons per day to about 8.9 million people in Texas, Louisiana, Mississippi, Arkansas, Missouri, Tennessee, Kentucky, Illinois, and Alabama. The Mississippi River Valley alluvial aquifer ranks third in the Nation for total withdrawals of which more than 98 percent is used for irrigation. From 1994 through 2004, water-quality samples were collected from 169 domestic, monitoring, irrigation, and public-supply wells in the Mississippi embayment-Texas coastal uplands aquifer system and the Mississippi River Valley alluvial aquifer in various land-use settings and of varying well capacities as part of the U.S. Geological Survey's National Water-Quality Assessment Program. Groundwater samples were analyzed for physical properties and about 200 water-quality constituents, including total dissolved solids, major inorganic ions, trace elements, radon, nutrients, dissolved organic carbon, pesticides, pesticide degradates, and volatile organic compounds.\r\n\r\nThe occurrence of nutrients and pesticides differed among four groups of the 114 shallow wells (less than or equal to 200 feet deep) in the study area. Tritium concentrations in samples from the Holocene alluvium, Pleistocene valley trains, and shallow Tertiary wells indicated a smaller component of recent groundwater than samples from the Pleistocene terrace deposits. Although the amount of agricultural land overlying the Mississippi River Valley alluvial aquifer was considerably greater than areas overlying parts of the shallow Tertiary and Pleistocene terrace deposits wells, nitrate was rarely detected and the number of pesticides detected was lower than other shallow wells. Nearly all samples from the Holocene alluvium and Pleistocene valley trains were anoxic, and the reducing conditions in these aquifers likely result in denitrification of nitrate. In contrast, most samples from the Pleistocene terrace deposits in Memphis, Tennessee, were oxic, and the maximum nitrate concentration measured was 6.2 milligrams per liter. Additionally, soils overlying the Holocene alluvium and Pleistocene valley trains, generally in areas near the wells, had lower infiltration rates and higher percentages of clay than soils overlying the shallow Tertiary and Pleistocene terrace deposits wells. Differences in these soil properties were associated with differences in the occurrence of pesticides. Pesticides were most commonly detected in samples from wells in the Pleistocene terrace deposits, which generally had the highest infiltration rates and lowest clay content.\r\n\r\nMedian dissolved phosphorus concentrations were 0.07, 0.11, and 0.65 milligram per liter in samples from the shallow Tertiary, Pleistocene valley trains, and Holocene alluvium, respectively. The widespread occurrence of dissolved phosphorus at concentrations greater than 0.02 milligram per liter suggests either a natural source in the soils or aquifer sediments, or nonpoint sources such as fertilizer and animal waste or a combination of natural and human sources. Although phosphorus concentrations in samples from the Holocene alluvium were weakly correlated to concentrations of several inorganic constituents, elevated concentrations of phosphorus could not be attributed to a specific source. Phosphorus concentrations generally were highest where samples indicated anoxic and reducing conditions in the aquifers. Elevated dissolved phosphorus concentrations in base-flow samples from two streams in the study area suggest that transport of phosphorus with groundwater is a potential source contributing to high yields of phosphorus in the lower Mississippi River basin.\r\n\r\nWater from 55 deep wells (greater than 200 feet deep) completed in regional aquifers of Tertiary age represent a sample of the principal aquifers used for drinking-water supply in the study area. The wells were screened in both confined and ","language":"ENGLISH","publisher":"U.S. Geological Survey","doi":"10.3133/sir20095091","usgsCitation":"Welch, H.L., Kingsbury, J.A., Tollett, R.W., and Seanor, R.C., 2009, Quality of Shallow Groundwater and Drinking Water in the Mississippi Embayment-Texas Coastal Uplands Aquifer System and the Mississippi River Valley Alluvial Aquifer, South-Central United States, 1994-2004: U.S. Geological Survey Scientific Investigations Report 2009-5091, x, 53 p., https://doi.org/10.3133/sir20095091.","productDescription":"x, 53 p.","temporalStart":"1994-01-01","temporalEnd":"2004-12-31","costCenters":[{"id":394,"text":"Mississippi Water Science Center","active":true,"usgs":true}],"links":[{"id":125594,"rank":0,"type":{"id":24,"text":"Thumbnail"},"url":"https://pubs.usgs.gov/thumbnails/sir_2009_5091.jpg"},{"id":12843,"rank":100,"type":{"id":15,"text":"Index Page"},"url":"https://pubs.usgs.gov/sir/2009/5091/","linkFileType":{"id":5,"text":"html"}}],"geographicExtents":"{ \"type\": \"FeatureCollection\", \"features\": [ { \"type\": \"Feature\", \"properties\": {}, \"geometry\": { \"type\": \"Polygon\", \"coordinates\": [ [ [ -102,25 ], [ -102,40 ], [ -83,40 ], [ -83,25 ], [ -102,25 ] ] ] } } ] }","noUsgsAuthors":false,"publicationStatus":"PW","scienceBaseUri":"4f4e4a8fe4b07f02db65513f","contributors":{"authors":[{"text":"Welch, Heather L. 0000-0001-8370-7711 hllott@usgs.gov","orcid":"https://orcid.org/0000-0001-8370-7711","contributorId":552,"corporation":false,"usgs":true,"family":"Welch","given":"Heather","email":"hllott@usgs.gov","middleInitial":"L.","affiliations":[{"id":105,"text":"Alabama Water Science Center","active":true,"usgs":true}],"preferred":true,"id":302888,"contributorType":{"id":1,"text":"Authors"},"rank":1},{"text":"Kingsbury, James A. 0000-0003-4985-275X jakingsb@usgs.gov","orcid":"https://orcid.org/0000-0003-4985-275X","contributorId":883,"corporation":false,"usgs":true,"family":"Kingsbury","given":"James","email":"jakingsb@usgs.gov","middleInitial":"A.","affiliations":[{"id":581,"text":"Tennessee Water Science Center","active":true,"usgs":true},{"id":37277,"text":"WMA - Earth System Processes Division","active":true,"usgs":true},{"id":451,"text":"National Water Quality Assessment Program","active":true,"usgs":true},{"id":24708,"text":"Lower Mississippi-Gulf Water Science Center","active":true,"usgs":true}],"preferred":true,"id":302889,"contributorType":{"id":1,"text":"Authors"},"rank":2},{"text":"Tollett, Roland W. 0000-0002-4726-5845 rtollett@usgs.gov","orcid":"https://orcid.org/0000-0002-4726-5845","contributorId":1896,"corporation":false,"usgs":true,"family":"Tollett","given":"Roland","email":"rtollett@usgs.gov","middleInitial":"W.","affiliations":[{"id":24708,"text":"Lower Mississippi-Gulf Water Science Center","active":true,"usgs":true}],"preferred":true,"id":302890,"contributorType":{"id":1,"text":"Authors"},"rank":3},{"text":"Seanor, Ronald C. 0000-0001-5735-5580 rcseanor@usgs.gov","orcid":"https://orcid.org/0000-0001-5735-5580","contributorId":3731,"corporation":false,"usgs":true,"family":"Seanor","given":"Ronald","email":"rcseanor@usgs.gov","middleInitial":"C.","affiliations":[],"preferred":true,"id":302891,"contributorType":{"id":1,"text":"Authors"},"rank":4}]}} ,{"id":97658,"text":"sir20095129 - 2009 - Groundwater-Quality Assessment, Pike County, Pennsylvania, 2007","interactions":[],"lastModifiedDate":"2017-06-13T10:19:09","indexId":"sir20095129","displayToPublicDate":"2009-07-09T00:00:00","publicationYear":"2009","noYear":false,"publicationType":{"id":18,"text":"Report"},"publicationSubtype":{"id":5,"text":"USGS Numbered Series"},"seriesTitle":{"id":334,"text":"Scientific Investigations Report","code":"SIR","onlineIssn":"2328-0328","printIssn":"2328-031X","active":true,"publicationSubtype":{"id":5}},"seriesNumber":"2009-5129","title":"Groundwater-Quality Assessment, Pike County, Pennsylvania, 2007","docAbstract":"Pike County, a 545 square-mile area in northeastern Pennsylvania, has experienced the largest relative population growth of any county in the state from 1990 to 2000 and its population is projected to grow substantially through 2025. This growing population may result in added dependence and stresses on water resources, including the potential to reduce the quantity and degrade the quality of groundwater and associated stream base flow with changing land use. Groundwater is the main source of drinking water in the county and is derived primarily from fractured-rock aquifers (shales, siltstones, and sandstones) and some unconsolidated glacial deposits that are recharged locally from precipitation. The principal land uses in the county as of 2005 were public, residential, agricultural, hunt club/private recreational, roads, and commercial. The public lands cover a third of the county and include national park, state park, and other state lands, much of which are forested. Individual on-site wells and wastewater disposal are common in many residential areas.\r\n\r\nIn 2007, the U.S. Geological Survey, in cooperation with the Pike County Conservation District, began a study to provide current information on groundwater quality throughout the county that will be helpful for water-resource planning. The countywide reconnaissance assessment of groundwater quality documents current conditions with existing land uses and may serve as a baseline of groundwater quality for future comparison.\r\n\r\nTwenty wells were sampled in 2007 throughout Pike County to represent groundwater quality in the principal land uses (commercial, high-density and moderate-density residential with on-site wastewater disposal, residential in a sewered area, pre-development, and undeveloped) and geologic units (five fractured-rock aquifers and one glacial unconsolidated aquifer). Analyses selected for the groundwater samples were intended to identify naturally occurring constituents from the aquifer or constituents introduced by human activities that pose a health risk or otherwise were of concern in groundwater in the county. The analyses included major ions, nutrients, selected trace metals, volatile organic compounds (VOCs), selected organic wastewater compounds, gross alpha-particle and gross beta-particle activity, uranium, and radon-222. Analyses of the 20 samples were primarily for dissolved constituents, but six samples were analyzed for both dissolved and total metals.\r\n\r\nResults of the 2007 sampling indicated few water-quality problems, although concentrations of some constituents indicated influence of human activities on groundwater. No constituent analyzed exceeded any primary drinking-water standard or maximum contaminant level (MCL) established by the U.S. Environmental Protection Agency. Radon-222 levels were greater than, or equal to, the proposed MCL of 300 picocuries per liter (pCi/L) in water from 15 (75 percent) of the 20 wells. Radon-222 levels did not exceed the alternative MCL of 4,000 pCi/L in any groundwater sample. Radon-222 is naturally occurring, and the greatest concentrations (up to 2,650 pCi/L) were in water samples from wells in members of the Catskill Formation, a fractured-rock aquifer. The dissolved arsenic concentration of 3.9 micrograms per liter (ug/L) in one sample was greater than the health-advisory (HA) level of 2 ug/L but less than the MCL of 10 ug/L. Recommended or secondary maximum contaminant levels (SMCLs) were exceeded for pH, dissolved iron, and dissolved manganese.\r\n\r\nIn six samples analyzed for dissolved and total concentrations of selected metals, total concentrations commonly were much greater than dissolved concentrations of iron, and to a lesser degree, for arsenic, lead, copper, and manganese. Concentrations of iron above the SMCL of 300 ug/L may be more widespread in the county for particulate iron than for dissolved iron. The total arsenic concentration in one of the six samples was greater than the HA level of","language":"English","publisher":"U.S. Geological Survey","doi":"10.3133/sir20095129","collaboration":"Prepared in cooperation with the Pike County Conservation District","usgsCitation":"Senior, L.A., 2009, Groundwater-Quality Assessment, Pike County, Pennsylvania, 2007: U.S. Geological Survey Scientific Investigations Report 2009-5129, vi, 53 p., https://doi.org/10.3133/sir20095129.","productDescription":"vi, 53 p.","temporalStart":"2007-01-01","temporalEnd":"2007-12-31","costCenters":[{"id":532,"text":"Pennsylvania Water Science Center","active":true,"usgs":true}],"links":[{"id":126869,"rank":0,"type":{"id":24,"text":"Thumbnail"},"url":"https://pubs.usgs.gov/thumbnails/sir_2009_5129.jpg"},{"id":12809,"rank":100,"type":{"id":15,"text":"Index Page"},"url":"https://pubs.usgs.gov/sir/2009/5129/","linkFileType":{"id":5,"text":"html"}}],"geographicExtents":"{ \"type\": \"FeatureCollection\", \"features\": [ { \"type\": \"Feature\", \"properties\": {}, \"geometry\": { \"type\": \"Polygon\", \"coordinates\": [ [ [ -75.5,41 ], [ -75.5,41.75 ], [ -74.5,41.75 ], [ -74.5,41 ], [ -75.5,41 ] ] ] } } ] }","noUsgsAuthors":false,"publicationStatus":"PW","scienceBaseUri":"4f4e4afbe4b07f02db69625e","contributors":{"authors":[{"text":"Senior, Lisa A. 0000-0003-2629-1996 lasenior@usgs.gov","orcid":"https://orcid.org/0000-0003-2629-1996","contributorId":2150,"corporation":false,"usgs":true,"family":"Senior","given":"Lisa","email":"lasenior@usgs.gov","middleInitial":"A.","affiliations":[{"id":532,"text":"Pennsylvania Water Science Center","active":true,"usgs":true}],"preferred":true,"id":302787,"contributorType":{"id":1,"text":"Authors"},"rank":1}]}} ,{"id":97637,"text":"sir20085240 - 2009 - Factors affecting water quality in selected carbonate aquifers in the United States, 1993-2005","interactions":[],"lastModifiedDate":"2022-02-16T21:47:51.399082","indexId":"sir20085240","displayToPublicDate":"2009-06-27T00:00:00","publicationYear":"2009","noYear":false,"publicationType":{"id":18,"text":"Report"},"publicationSubtype":{"id":5,"text":"USGS Numbered Series"},"seriesTitle":{"id":334,"text":"Scientific Investigations Report","code":"SIR","onlineIssn":"2328-0328","printIssn":"2328-031X","active":true,"publicationSubtype":{"id":5}},"seriesNumber":"2008-5240","title":"Factors affecting water quality in selected carbonate aquifers in the United States, 1993-2005","docAbstract":"Carbonate aquifers are an important source of water in the United States; however, these aquifers can be particularly susceptible to contamination from the land surface. The U.S. Geological Survey National Water-Quality Assessment (NAWQA) Program collected samples from wells and springs in 12 carbonate aquifers across the country during 1993–2005; water-quality results for 1,042 samples were available to assess the factors affecting ground-water quality. These aquifers represent a wide range of climate, land-use types, degrees of confinement, and other characteristics that were compared and evaluated to assess the effect of those factors on water quality. Differences and similarities among the aquifers were also identified. Samples were analyzed for major ions, radon, nutrients, 47 pesticides, and 54 volatile organic compounds (VOCs).
Geochemical analysis helped to identify dominant processes that may contribute to the differences in aquifer susceptibility to anthropogenic contamination. Differences in concentrations of dissolved oxygen and dissolved organic carbon and in ground-water age were directly related to the occurrence of anthropogenic contaminants. Other geochemical indicators, such as mineral saturation indexes and calcium-magnesium molar ratio, were used to infer residence time, an indirect indicator of potential for anthropogenic contamination. Radon exceeded the U.S. Environmental Protection Agency proposed Maximum Contaminant Level (MCL) of 300 picocuries per liter in 423 of 735 wells sampled, of which 309 were drinking-water wells.
In general, land use, oxidation-reduction (redox) status, and degree of aquifer confinement were the most important factors affecting the occurrence of anthropogenic contaminants. Although none of these factors individually accounts for all the variation in water quality among the aquifers, a combination of these characteristics accounts for the majority of the variation. Unconfined carbonate aquifers that had high percentages of urban or agricultural land, or a combination of both, had higher concentrations and higher frequency of detections for most of the anthropogenic contaminants than areas with other combinations of land use and degree of aquifer confinement. Redox status is an indicator of more recently recharged water and affects the fate of some contaminants.
Median concentrations of nitrate were highest in the Valley and Ridge and Piedmont aquifers and lowest in the Biscayne and Silurian-Devonian/Upper carbonate aquifers. Nitrate concentrations were significantly higher in unconfined aquifers than in confined aquifers and semiconfined/mixed confined aquifers (wells in aquifers with breached confining layers or wells open to both a confined and an unconfined aquifer). Water recharged after 1953 had significantly higher concentrations of nitrate than water recharged prior to 1953. Redox status was also a key factor affecting nitrate concentrations; in recently recharged waters, samples in oxic waters had significantly higher concentrations of nitrate than anoxic waters, regardless of land use in the area around the well. Samples from 54 wells (5 percent) exceeded the U.S. Environmental Protection Agency MCL of 10 mg/L for nitrate in drinking water. Most of the samples exceeding the drinking-water standard (52 samples, or 5 percent) were in domestic supply wells in agricultural areas. The Piedmont and Valley and Ridge aquifers had the largest number of samples (45) exceeding the MCL; in the remaining aquifers only 9 samples had concentrations of nitrate that exceeded the MCL (about 1 percent). None of the water recharged prior to 1953 and only a single sample from a confined aquifer had nitrate concentrations that exceeded 10 mg/L as N.
Wells were sampled for a minimum of 47 pesticides. Detection frequencies and comparisons varied depending on the assessment level used. At least 1 of the 47 pesticides was detected at 510 (50 percent) of the 1,027 sites where pesticide data were available using the ‘all detections’ assessment level—that is, including any quantified detection as well as any estimated values where the compound was definitively detected. Multiple pesticides were frequently detected in a sample of water from a site; 34 percent of the samples had two to five pesticides detected in the same sample, and 4 percent of the samples had six or more pesticides detected. Dieldrin was detected at 20 sites, 9 of which were from either domestic or public supply wells, at a concentration above the Health-Based Screening Level (HBSL) of 0.002 µg/L. Diazinon was detected at a concentration greater than the HBSL of 1 µg/L at a single site, which was also a domestic supply well. These are the only samples where a pesticide exceeded a human-health benchmark.
The most frequently occurring pesticide compounds were four herbicides—atrazine, simazine, metolachlor, and prometon—and deethylatrazine, a degradate of atrazine. These pesticides typically were detected at concentrations that were less than 10 percent of a human-health benchmark. Of the four frequently occurring pesticides, only samples for atrazine (3 percent) and simazine (0.1 percent) had concentrations that exceeded 10 percent of the human-health benchmark; most of these cases were in agricultural areas. It is important to note, however, that the most frequently occurring pesticide degradate compound—deethylatrazine—has no human-health benchmark. Using a common assessment level of 0.01 µg/L, four of the aquifers—Biscayne, Mississippian, Piedmont, and Valley and Ridge—had at least one of these five compounds detected in more than 30 percent of the wells sampled. These four aquifers, along with the Ordovician, Ozark Plateaus, and Prairie du Chien aquifers were the aquifers or aquifer systems that had concentrations of pesticides that exceeded 10 percent of a human-health benchmark. Water recharged after 1953 had a significantly higher percentage of detections of pesticides than water recharged before 1953, and water from unconfined aquifers had a significantly higher percentage of detections of pesticides than water from confined or semiconfined/mixed confined aquifers. Water from sites in unconfined aquifers, where land use was agricultural or urban, accounted for the vast majority of detections of pesticides. Dissolved oxygen concentration was positively related to pesticide occurrence, which likely reflects the positive association between dissolved oxygen concentration and recently recharged water.
Water samples were collected for analysis of VOCs at 793 sites—154 samples were analyzed for 54 VOCs from 1993 through 1995 and 639 samples were analyzed for 86 VOCs from 1996 through 2005. Twenty percent of samples contained one or more VOCs at concentrations greater than or equal to 0.2 µg/L (159 of 793 samples). The aquifers with the highest percentage of samples containing one or more VOCs were the Castle Hayne (about 41 percent of samples) and Biscayne aquifers (34 percent). The most frequently detected VOCs were chloroform, tetrahydrofuran, tetrachloroethene (PCE), toluene, acetone, ethylmethylketone, methyl tert-butyl ether (MTBE), and trichloroethene (TCE). Low-level concentrations of VOCs occurred in a much larger percentage of a subset of the data (the 639 samples analyzed using a low-level analytical method). In these samples, 69 percent of the 639 samples contained 1 or more VOCs, indicating the vulnerability of the carbonate aquifers to low-level VOC contamination. Four VOCs were detected at concentrations exceeding their respective MCLs in five samples, all of which were from drinking-water wells. Vinyl chloride concentrations exceeded the MCL of 2 µg/L in two samples from urban areas in the unconfined Biscayne aquifer. PCE, TCE, and 1,2-dichloropropane each had one sample with a concentration greater than their MCLs of 5 µg/L; these samples were from agricultural and urban areas in the unconfined Mississippian aquifer.
Water quality in the 12 carbonate aquifers was highly variable. Most of the samples met drinking-water standards. The occurrence of anthropogenic contaminants was related to contaminant sources but also was affected by degree of aquifer confinement, ground-water age, and redox status. Areas with higher amounts of agricultural or urban land in unconfined aquifers were the most likely to have elevated concentrations of anthropogenic contaminants.